Metric Ruler

Accuracy


48% voted correct
Please set your diagonal monitor size (in inches):
Not sure what your monitor size is ?
Metric Ruler Actual Size Image

285 Comments


Anonymous
this is AWESOME!
Anonymous
on 20 cm 2 mm to long!
Anonymous
perfect here! 19"
Anonymous
way too big on 13"
Anonymous
it's 7 mm longer on my 15"
Anonymous (24" monitor)
perfect on a 24"
Mercury (26" monitor)
5mm under 25 cm on my 26 inch
equinox (22" monitor)
0.5mm to short on my 22"
Anonymous (17" monitor)
perfect
Steve (13" monitor)
It's perfect on my 13.3" Macbook.
S.M. D**k (23" monitor)
Perfect on 23"
Sumguy (17" monitor)
I guess its right but I have no way to tell
anonymous (21" monitor)
2mm to small on 21" crt
Anonymous (20" monitor)
DIRECTIONS!!

you have to enter the actual viewable portion of your monitor not the whole size.

Example:
I have a 21" crt but there is a Black box on the outside of where my screen starts to work. it just happens to be .5 inch on both sides so
21 minus 1 =20 inch monitor size.
BobO (15" monitor)
perfect on my 15"
Robby (17" monitor)
How do you know if its wrong? why would you look up an online ruler if you had a way to measure it?
D**k (2" monitor)
I Agree With Robby, It Kinda Makes This Website Obsolete! You Guys Just Put Yourself Out Of Jobs, Way To Go...!
Anonymous (23" monitor)
i dont like it your the worst person ever i hate you
fussy (22" monitor)
perfect on a 22"
Brandon (19" monitor)
Perfect on 19" 1440x900
mystery (40" monitor)
I can't see it
m.man (40" monitor)
hard to see
anonmisno (12" monitor)
fake-doesn't wrk fr me
u wish man (15" monitor)
it is so big i had too get another ruler too measure it
WHAT (2" monitor)
I have no idea what to do?????
secrets (14" monitor)
omg i'm so excited for my gems to come in the mail
bugannoyer (14" monitor)
Assuming 8.5in wide paper is exactly that, came out 1mm over, so pretty accurate. 14.1in laptop display.
arab (14" monitor)
this is great... helped me finish organic chem lab
riiiiiight.... (15" monitor)
How long did you say a bed bug is? ... oh, c**p. It got away!!!
namename (22" monitor)
22" is perfect i think
justin (15" monitor)
about perfect on my 15.4" laptop screen, on google chrome
Yannis (17" monitor)
Juuust about perfect on my 17", only a mere 0.9 of a cm larger than it should be but I certainly find it accurate.
Victoria (7" monitor)
works perfect on my 15 in laptop but the scroll bar gets in the way so when i move it over a tad bit i know its on 15 or h**l of alt close
Kevin (13" monitor)
This changes in respect to your browser sometimes, because browser can display at different sizes
bob (19" monitor)
1mm long on 19"
Jasmine (13" monitor)
IMMMMMMMM MADDDDDDD.
im trying to use this for my homework but ...
do you have any different type of cm rulers because this one only has 10ths!
I needd 12thss!
PLEASE.
mari (18" monitor)
this works!! 18'' safari!!
Anonymous (14" monitor)
dang i dont know how big my moniter is! how am i supposed to measure it without a ruler?
Anonymous (14" monitor)
slightly too long x2.
Another Guy (16" monitor)
Isn't this just fake. You put in different screen sizes and it just enlarges.
FAKE FAKE FAKE!!!
#43 people #43
Another Guy (16" monitor)
#35
Anonymous (17" monitor)
This is perfect i dont know what the f**k is wrong with some of these idiots.
Perfect on my 19" monitor NOT widescreen.
Anonymous (17" monitor)
^ By the way im using Google Chrome if thats imporant
azza (17" monitor)
exact right on my 57 inch pc :)
bhfghgd (190000000" monitor)
ghjcgjkjgknlj,;ghgljk
dude101 (190000000" monitor)
wow dude
Egyptian (20" monitor)
It's a little short, but good enough :D
ME (14" monitor)
Welll, I Didnt Measure It.. But It Loooks Absolutely Correct On My 14.1" screen. And Also I Was Using Google Chrome.. If That Seems To Be Important? :S
Duh (12" monitor)
This is goofy - I am LOOKING FOR A RULER!! How can I measure the exact dimensions of my screen WITHOUT A RULER??? Maybe the screen size should be requested as "Number of ballpoint pens lined up end-to-end across the screen (but not down). 2.25 pens, to be exact.
losah (12" monitor)
kool
beauty..brapp (3" monitor)
butterzz c**p
beauty..brapp (3" monitor)
my monitor in 16inchess ???
Anonymous (15" monitor)
muchh betterr
60th comment loool (15" monitor)
yeeeyyyy!! 60th comment :P
anonymous (10" monitor)
horrible no write measurements except on 13"
anonymous (10" monitor)
horrible no write measurements except on 13"
anonymous (10" monitor)
there is this boy in my class who is so cute but i cant tell him i like him because i am too popular
anonymous (10" monitor)
people who go on this website r freshis ,loners , and sados
Johnson (14" monitor)
Perfect on 14.1 inch
Anonymous (16" monitor)
lol at 64, since he's here himself
Bill (15" monitor)
I read my Dell manual, specifications page. It said the screen is 15.4". The on-screen rule is exactly right. I can think of lots of times I can't be bothered to get a ruler but want to know the size of things I'm looking at on Ebay etc.. Guess it takes imagination to see the value in something.
Kian (19" monitor)
Perfect on 19''
Anonymous (24" monitor)
7inches umad?
Anonymous (18" monitor)
woooo i has a 2 cm long nail

which i just broke off :P but it was 2cm before i broke it
Tom (23" monitor)
Dead on for a 23" screen. Thanks!
fREAkylUCi0US<3 (12" monitor)
WEll i dEw aqREE wiTh tHE oTHeR qUy
cUz diZ iS FAkE . WhO iNvEnTeD diZ c**P :p
WHY (10" monitor)
i don't know which one is millimeters.
?!?!?!? (13" monitor)
when i go to the office supplies store to buy a ruler, they don't say "here is a ruler but please check it against another ruler to ensure accuracy."
NOPE! (12" monitor)
it doesnt show it diagonally and thats what i want!!!!!!!!!!!!!!!11
Cameron (15" monitor)
After 20cm it's 8mm out
Dollar (17" monitor)
good one!!!!!!!!!!
Dt (16" monitor)
bang on!!!
A Cat That Can Type (19" monitor)
Um... I agree with number 55... ironic huh? Looking for a ruler and i'm asked to measure something? <O.o> Meow.
A Cat That Can Type (19" monitor)
hmmmm... apparently my monitor is 19"... Thanks pective.com!
bad (4" monitor)
bad
mr. bill (16" monitor)
purty sure its spot on. All the other random stuff that i checked on this site matched up, and although i don't have a metric ruler, I see no reason why this would be randomly incorrect.
mr. bill (16" monitor)
hey, wth. my monitor size at the top says 15.6 (because it is), but on my comment it clearly says 16. odd.
Zebulon (24" monitor)
Accurate at 23.6" Thanks!
an (19" monitor)
this is awsome!!!!!!!!!!!!!!!!!!!! lucky to know my monitor size xD
col (17" monitor)
I know my screen is 17"

Do I know how accurate the measurements of this on-line ruler are?

No.

You see, I was looking for a ruler or tape-measure around the house and couldn't find one.....

Will I come back to this site and measure the ruler on the screen with another ruler?

No.

i'm with the last guy on this...

WHO GOES TO AN ON LINE RULER WEBSITE JUST TO MEASURE HOW ACCURATE THAT ON LINE RULER IS????

Only the sort of people who would respond this comment I guess....

Don't bother, I'm off to buy a new ruler, so won't be back.
american13 (4" monitor)
this is OK i guess
Bakedpotatoes (14" monitor)
D**n, not quite right. I'm pretty sure there are some small programs you can get that display a ruler on your screen for you, those ones are good.
hmmm (26" monitor)
Maybe there are some people for whom it works, but I just tried it out and for me it is absolutely wrong. The difference between a real tape measure and this badly programmed something was about 15 % ....
Jake (10" monitor)
dis bull s**t
DrP (15" monitor)
Off by 1mm every 30mm in my 15''
Vicent (13" monitor)
20 cm, me parece que no!... con esto se la miden algunos! y se van tan orgullosos!
jajaja
Grr (15" monitor)
i haven't got a ruler to measure my monitor size >_<
mrt (17" monitor)
works on 17" - 1920x1200
operator (17" monitor)
worked good on my 17" , less than 1/2 a MM off after I used it and had the time later to go back and check, works in a pinch
lolololol (11" monitor)
nice job geeks!
EZ (11" monitor)
FREAKING AWESOME!!!:)
donald duck (20" monitor)
This website is dumb
TeslaCoilGirl!!! (19" monitor)
LOL our control experiment
laffy funny tim (20" monitor)
it is perfectemundo hehehaa

meoww ruffity ruff ruff limbonian
laffy funny tim (20" monitor)
it is perfectemundo hehehaa

meoww ruffity ruff ruff limbonian
Pat (15" monitor)
Had to set to 15.22 to get it right
Anonymous (12" monitor)
thts wat she said on all these comments LOL
Anonymous (17" monitor)
Works!

Measured it with a ruler...

-17'' Macbook
M&M (16" monitor)
Its perfect on my laptop screen. Never thought how significant 3 cm can be. Just found out I have a 3 cm tumor in my ovary, needed to know exactly what 3 cm looked like
lucy (13" monitor)
this didnt help me with mm and i dont count the size of my montior how would i know ?
rfmnva (15" monitor)
Perfect on my 15.4" MacBook Pro. To #55, I didn't know my exact screen size either, but I looked up the tech details on line. Hope that helps.
mae (17" monitor)
works great on 16.5"
Jan (12" monitor)
Great tool!
Anonymous (19" monitor)
Looked right but when I finally got off my chair and looked for a ruler (my curiosity got the better of my laziness) ... the online ruler was 15mm short. I don't think this site was designed for 19" widescreens. What a waste of time... next time I'll just use real life stationary instead of visiting superflous sites like this one.
none (17" monitor)
this f*****g sucks
me? (16" monitor)
basically, if u go on iruler.net = the website measures the size of your screen for you, if u go on that website under the big ruler that will come up on the screen its printed a bit smaller right under it how big ur screen is and then all u gotta do is take these measurements to this website her and put them in that little box lol :)
Christianini (19" monitor)
0,5 mm longer in a dell 19"
ConstiB (10" monitor)
*********************************************************************************
ZERO % ACCURATE....As In "COMPLETELY WRONG ON iPAD."

Re: Metric Ruler, i.e., cm, mm

On a First Generation iPad......Inside the black area on mine is 9.5 inches using a wooden ruler (the guide says 9.7). Adjusting for that...the metric ruler says 35% accurate, but it's 100 % WRONG!

********************************************************************************
petrus (22" monitor)
perfect on 22"
Elias (23" monitor)
PERFECT! 23''
poop (7" monitor)
well im you guys would put in the length of your screen you wouldnt b saying it doesnt fit!!!!!!!!!!! GAWD
GotMILK? (50" monitor)
Umm.... Someone please tell me any objects that are 50cm in length.??
yo (16" monitor)
works for an inspiron 15.6 inch
Mat (14" monitor)
If you don't have a ruler use a peice of A4 paper fold it in half and the short side should measure 14.8cm. It's close enough for me on 14.1inch 1280*900 16:10 screen.
tom (15" monitor)
is this site stupid i need a ruler to mesure the screen and if i had a ruler i would never of come on this site
.
Meme (17" monitor)
Cool my c***s a lot bigger now!!
ME (20" monitor)
This is sort of accurate...
me (16" monitor)
ang hirap nman
Danielle (17" monitor)
2 mm short on my 17" monitor. I have a ruler with inches only, so I looked up the conversion and did it that way...so it is an estimate. But I think it is pretty accurate. I just wanted a general idea of how big a 5 mm diameter is, so I can order some beads. Next time I will just convert to inches since I have that ruler on hand. But if I find myself without any ruler at all, I will come back here and use it.
personelle (10" monitor)
works amazingly on my 10.1 netbook!! :)
Anonymous (20" monitor)
Perfect on Syncmaster 206bw (20in viewable area). I'm holding up a ruler to the screen and it's spot on.
AlphaQ (12" monitor)
0.5 mm short on my 11.6" NetBook monitor (Acer Aspire One), using Google Chrome. Way better than I expected!
For people who are complaining, please enter the exact VIEWABLE size of your monitor.
Learnt about this site from BBC's CLICK.
Big'en (18" monitor)
8.5inch, yeh seems right.

Oh sorry, thought we were sharing p***s sizes!
Anonymous (15" monitor)
16CM is 15.5 CM!!!
Doublecheck (17" monitor)
It was a little off with my 17" screen, but that could have been because the measuring tape was stretched slightly (for an accurate measurement, you can't use measuring tools that distort (stretch) such as sewing measuring tape. You have to use a wooden, metal or other type of material that won't pull.) Another thing is the VIEWABLE screen size. It could be that the viewable screen size is the size INSIDE the browser window plus the task bar at the bottom. I subtracted 1/10" making mine 16.9" and it was perfect (according to my possibly stretched sewing measuring tape...). If you want yours absolutely perfect, get a good ruler. Believe it or not, there ARE uses for having an accurate online ruler, whether YOU use it or not, someone else does. So if you don't need it, fly away. You don't have to add snarky comments to this page. If it doesn't work at all for you, there's also a reason. Maybe it's a plug-in you're missing.. Java, for instance. It works for others, so obviously it's not fake. Get the plug in, or fly away.
ginger (16" monitor)
Well, if its waaaay off, then try adjusting the size to actually fit your screen. Dummmmies.
mganstin (15" monitor)
hey that's not necessary, ginger. It may not work correctly on every computer, (including mine), so the only dummy here is most likely the one who tells others that they are dummies.
Kana (15" monitor)
Perfect on my 15,1" monitor =)
Azam Ali (17" monitor)
This is a great tool Thanks.
Anonymous (14" monitor)
It is accurate.
VoxAppeal (24" monitor)
I'm guessing it's 'about' right, but if I could check it then I wouldn't need it. That's why I came here in the first place.
Anonymous (23" monitor)
Bugs for me, probably as I'm on a 5760x1080 resolution setup.
its Me (15" monitor)
Amazing,on the dot - accurate on my 15.3" screen Toshiba. Now I dont need a foot ruler to measure myself!!
l; (58" monitor)
you ant use it twice
chocolate lover (7" monitor)
sooooo awsome i love this the helped me with my home work . if i ever need a ruler for home work i will ues this be for any other
Hello (10" monitor)
Perfect!
Awesome Ruler!!! (16" monitor)
Helped me estimate the size of a new RC Car I ordered
i say (16" monitor)
accurate
ERICA! (15" monitor)
I was just making sure the barrettes I am buying on Ebay are the right size. There's 30mm, 40mm, 45mm, 50... You get the picture? Only ruler I could find had no metric and God Forbid! I find one of the 30 rulers we have to have around this house! Such a neat tool for figuring out the size of your screen! Awesome tool indeed!
wtfcccck? (9" monitor)
s***s gay -,-
wtfcccck? (9" monitor)
i get it now .. Never mind you have to change the monitor size to the correct number in order for it to work (:
wtfcccck? (9" monitor)
I have a 8.5 inch monitor so I did all my fuckenq math and science homework wrong thanks too yooou fucckennq asss hooles !! !! chooke onn a treee yooou BIIRDDS
Unicorn-xo (12" monitor)
This is brilliant! So perfect. (You have to click 'Incorrect' and it allows you to measure it to an object e.g - credit card, coin.
Mines a 12inch :P cheers xP
youtuber (13" monitor)
http://www.youtube.com/user/livelaughsmilesing?feature=mhee

I'm a singer!!!
anon (16" monitor)
perfect, exact measurement
A+ (16" monitor)
Got through my homework in no time! totally accurate!
tony (19" monitor)
thanks
Anonymous (15" monitor)
Thankyou for this very helpful website...I found it very useful after measuring a cd on the screen and adjusting the size, as you suggest. It was really accurate :-)
I don't understand why people have to be so rude, offensive and downright thick. They live very sad lives, obviously :(
no homo (15" monitor)
Works for me!!!!!!!!!!!!!!
gay (6" monitor)
say my name lol this was funny cuz its a ruler on da comp
stupid (12" monitor)
i dont care stupid head of me
Macbook air 11" (12" monitor)
I put it to 11.56 and it's correct here!
hello (15" monitor)
i put 15 (my screen is 15,6 and it worked)
ngfdnfxbfdx (16" monitor)
really helpful. now in case its wrong id better go buy an actual ruler.
#171 (20" monitor)
thank you!! trying to do ma tech homework and this helprd loads!! the cd test is a very good idea and this helped moi loooaaddssss!! :) thannnkksss
ash (17" monitor)
just needed my screen size, and it was pretty accurate

also some of these comments are f*****g hilarious
annyo (15" monitor)
if you typed the wrong number for screen size.... how do you change it after submitting it?!?!??!?!!!!!!!!!!!!!!! so f*****g annoying
annyo (16" monitor)
wait i found it... at the top!
Samer (15" monitor)
it will be perfect on 51.4" monitor when you change zoom level to 95%

Try it.....
Samer (15" monitor)
Sorry 90%
adina (12" monitor)
perfect! :-D thanks!
Panda (19" monitor)
Didn't work on widescreen so I got my old Helix school ruler out.
dekittin (14" monitor)
Works best on 13.9" to me, my monitor is 14". Just 'lil touch of recalibration offered by pective.com somewhere in this site.
Anonymous (21" monitor)
Off. 21" monitor....1.2cm off
123456789101112131451 (40" monitor)
dumb
123456789101112131451 (40" monitor)
dumb
Unknown (17" monitor)
Wow... It's the actual size! :D
robbo (15" monitor)
if I had a ruler I would not have searched for an on screen ruler!

who are all the people who had a ruler but still found this site?

It is an even stranger world than I thought... :-)
martha (17" monitor)
1 mm too large compared to accurate steel measuring device. iMac G5
17".
g00dman (17" monitor)
this works great
135 (10" monitor)
go on 10 it's awesome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
lolo (13" monitor)
wow i got a big d***! Maybe I typed my monitor size wrong....
wow (20" monitor)
come on people, you should be able to look at your monitor and tell about what size it is. take a guess and compare a nickel to the one on the screen. (double click the nickle first)
Ivan (20" monitor)
excellent!
Frida from Hackforums (19" monitor)
I'm suckin d**k day and night.
Anonymous (15" monitor)
13" wow i typed 15
metricus (15" monitor)
15.4" works good, enter the exact monitor size, otherwise it won't work that good.
Rathah (16" monitor)
Works in Chrome, not IE9
maggi (12" monitor)
awesome! people who say it doesn't work, u r stupid and need to learn how to use a frickin laptop or computer.
znaso (17" monitor)
love it!!! very helpful!
Adolf Hitler (19" monitor)
Well, it works for me, don't know if it's the actual size. Seem legit.
ppitzer (19" monitor)
very clever and useful.
prashant (16" monitor)
lovely n very useful
ghffrdgfv (18" monitor)
you guy are crazy
Ed (13" monitor)
if you don't know your screen size just use the "don't know" feature. a dollar bill is 15.5956 cm long (6.14in) if you really must measure.
Lihatiski (24" monitor)
12,3cm ove 10cm actual on 24''
willy (10" monitor)
THAT IS AWESOME!!!!!!!!!!!!!!!!!
EDDY (10" monitor)
HOW IS THAT STUPID WHO EVERY SAID THAT THEY ARE!!!!!!!!!!!!!!!!
Inexpensive (6" monitor)
This ruler is correct. My d!c& measures right at 5.75" which is .25" short of my screen size. I assure you this is correct.
maw (4" monitor)
It worked great.
Anonymous (15" monitor)
thanks for this metric ruler
it's a good ideea! if is not wery precise for some people...1% but is a good help when u want to aproximate something, (some people talk because they not have what to do with time) good work! worked fine!
Phaedra (27" monitor)
Thanks; it really came in handy on my 27" screen.
Valerie (6" monitor)
Where do you go if you want cent.?
Valerie (6" monitor)
Oh it is ha
Andy (6" monitor)
Wow this works great
Shirly (6" monitor)
I agree this was a great idea, thanks!
UFBC (20" monitor)
Works well on my 22" when I type in the correct 20.1" visible screen size.
Anonymous (22" monitor)
Perfect on 21.5"
Markus (23" monitor)
Perfect
LG 23" 3D LED Monitor
also Perfect on my
AOC 23" LED Monitor

All you idiots who complain - study some basic geometry and screen translations - this is mathematical, if you entered correctly and remember to compensate (those who use crts) for screen bending and screen bounding box then it will work perfectly!
Anonymous (22" monitor)
welp, now i only have to put my p***s against the screen to measure it
Santi (16" monitor)
Great website! Well done! :)
sex (16" monitor)
i used this to measure my d**k
Anonymous (17" monitor)
17.1" viewing screen, right size. Yes I check with a ruler. I like this idea. I have kids and I can't find a ruler when I need one. Plus I sometimes misplace it myself.
Sparkicus (15" monitor)
Enter "15.4" for a 15" screen and it should then be right on the money. (at least on my MacBook Pro 15")
SONIC-BOOM! (17" monitor)
didnt bother to measure it exactly but it looked close enought for what i needed ;)
nada (15" monitor)
i thimk this is wrong........scale just got expanded, measured length of my pencil by setting screen size 11 inch , was 7.7 then when i set it at 15 inches, length measured came out 9.4 .
anaua (10" monitor)
im sure this is all s**t
Anonymous (15" monitor)
my monitor is supposedly 16.3" but i used a compact disc to make the scale perfect and it was 15" and then i found a ruler and compared and it was correct
that was weird but at least it worked correctly
Anonymous (30" monitor)
Yep mine was 2mm longer at 20cm.
Anonymous (19" monitor)
Doesn't work!
ajay (18" monitor)
really awesome
but need small corrections :)
zoë Bee (16" monitor)
Love It! Now I can bake cheesecake in my only just-too-small pan, woot!
naxxi (12" monitor)
works for me
laz (16" monitor)
spot on
Anonymous (16" monitor)
1cm short on 15cm ruler
Anonymous (16" monitor)
1cm short on 15cm ruler

Monitor Size= 15.6'' (not 16'')
Anonymous (24" monitor)
perfect on my 23.5" monitor. just adjust your monitor size correctly!!!
Anna (14" monitor)
PERFECT! this is helps me find mesurments from european to american!
anon (15" monitor)
good
Gil (16" monitor)
Nice! Very handy!
Alex (16" monitor)
16'' measured 3.4mm just fine. Great job
Anonymous (12" monitor)
wow i have a 11 inch p***s
Anonymous (13" monitor)
you can use paper money to get the exact size of your computer...
(go to right top and press the monitor size button)
Ronny Roberge (10" monitor)
#27 has a 2 inch monitor. Look how small it is:
http://pective.com/pic/2-inch-monitor
john (13" monitor)
good at 12.1' screen
Anonymous (15" monitor)
AWESOME, INTERNET HAS EVERYTHINGGG
Anonymous (17" monitor)
how do you change your monitor settings if they are incorrect?
Anonymous (17" monitor)
THIS F****N THING IS WRONG
Anonymous (15" monitor)
perfect on 15.4"
Anonymous (23" monitor)
Coolest thing EVA!!
Terri C. (19" monitor)
It came out PERFECT!! I printed out other cm/mm rulers and they all didn't match the ruler I had. So started to think wow is the ruler off. But after putting in diagonal size of monitor in, wahlah! perfect!! thanks!
kostas (17" monitor)
It's exactly on!!! Amazing!!!!
Nicholai (15" monitor)
Make sure you enter your actual screen size — it's often different than the advertised size.
Anonymous (15" monitor)
Works well! Thanks!
Anonymous (21" monitor)
very usefull and accurate thanks
Anonymous (18" monitor)
excellent!
ddd (7" monitor)
too big
a nony mouse (19" monitor)
sick blad, mofo b***h gonna be on yo d**k fo dis - fo sho
H28 (15" monitor)
Dead on for my monitor. Thank you.
NexusDrake (32" monitor)
it doesnt work on my 32 inch monitor
Vishwanath Taykhande (17" monitor)
A perfect ruler!
Oliver (17" monitor)
Works perfectly, but it would be nice if we could print it.
Anonymous (14" monitor)
it is accurate
Joey Joe-Joe Jr. Shabadoo (22" monitor)
This is a fantastic tool. Thank you! Although I just found out my pen1s is only 3cm long :(
Billy Alaway (19" monitor)
no way #4 do you know how to measure
Duh (11" monitor)
In order to display a ruler in its actual size, two details should be known: screen resolution and monitor size.
Your browser determines and exposes your screen resolutions, but there is no way to certainly know your monitor size without explicitly selecting it.
So, when you select your monitor size the site calculates and sets the pixel size of a ruler image and the result is accurate ruler in its actual size.
Miss Accurate (22" monitor)
I entered my correct monitor size, and when I put an actual metric ruler up to the metric ruler image on your site, yours was 2 mm short. People should not rely on this for accuracy.
Mr Retina (5" monitor)
On Mac Pro Retina 15'' not accurate :/
pope (17" monitor)
ok
virus trojan (17" monitor)
very very very too so accurate
boss (8" monitor)
Amazing
Sam (17" monitor)
Works great on my 2,300 inch mega viewer.
Mark Zuk (19" monitor)
You have to put resolution in options and not inches... that's why there are so many mistakes out there. In my 4:3 19" it worked well though.
HEYEAYEAYEA (18" monitor)
Perfecto!
Oh well (22" monitor)
Size DOES matter
15,65 inch (16" monitor)
quite accurate
noname (16" monitor)
Fail
tom g (14" monitor)
14' acer accurate
long john (24" monitor)
my c**k is 18cm!! nice!
Goku (11" monitor)
I don't get how to use this
Paul (20" monitor)
PERFECT on a 20 inch monitor. I double-checked the measurements with an actual ruler. Nice!
fritzy (23" monitor)
walay ans/?//////?
Master (24" monitor)
You should make a vertical ruller too
Anonymous (13" monitor)
Perfect on 75mm and 100mm using a US Dollar to size the screen
Hysterics (9" monitor)
Fab on the 7 over cooked on 180 needs more work on a 10 prefer 3D and 4G ... Don't get this at all,
r (21" monitor)
s
Dawg (17" monitor)
works just right on 17"
Annonymous (20" monitor)
Accurate on 20" screen, helps if you have your zoom set to 100%
Anonymous (8" monitor)
Wrong
Keerthi ram (14" monitor)
Perfect!
Anonymous (23" monitor)
perfect on 23"
goober (15" monitor)
great on my 72"
CVT (23" monitor)
if your monitor is not LCD or LED (flat), it won't work properly. on my 23'' monitor, it's perfect.
Griffin (16" monitor)
perfect measurement on my 15.6 in screen, it saved my a*s when I looked at my Microbio homework and realized I needed a ruler :/
Michael (19" monitor)
Perfect on 19 in.
fas (12" monitor)
gaga
thanos (22" monitor)
Using my EXACT screen size, (e.g. care for 21,5'' and not 22'') this measures A4 paper exactly 21, which actually is 21*29,7.

100% spot on, AWESOME
John Wulf (19" monitor)
Perfect on my 19 in monitor
Anonymous (18" monitor)
almost perfect!
Anonymous (18" monitor)
almost perfect!
Blah man (70" monitor)
Bad
Blah man (70" monitor)
Bad
Blah man (70" monitor)
Bad
RX (16" monitor)
PERFECT! for 16 Toshiba Satellite. Thanks!
GREAT (24" monitor)
perfect 12" long. Only complaint is that I had to clean my monitor after because I couldn't contain myself.