# Millimeters to Fractional Inches Conversion



## hokieman (Feb 14, 2008)

I have been working with Blum drawer slides and soft close hinges and much of the installation instructions are in millimeters. I found this handy program for converting millimeters to fractional inches. http://www.rapidtables.com/convert/length/mm-to-inch.htm

I just downloaded this on my phone and bookmarked it and it is always available to me in my shop. The most difficult part of this is trying to find 19/32 of an inch on my rule! Maybe one day the US will convert to metric but I doubt it.


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## corelz125 (Sep 23, 2015)

I use an app on my phone for conversions. Its called handyman calculator by kalyani also has a ton of other features for measurements


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## MadMark (Jun 3, 2014)

35mm Cup centers @ 13/16 & use a self center #8 drill pilot for the screw hole.

M


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## Andybb (Sep 30, 2016)

Thanks. I will check out the app but as handy as my phone apps are, when I'm in the shop these are much faster for me. I just put them in a plastic sleeve attached by a string to hang on the side of my bench and router table respectively. I *always* know where they are. Low tech in 1/64ths".

My other trick for stuff less than 6 inches is to use my calipers and and let it do the conversion for me.










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I like this one also.


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## wormil (Nov 19, 2011)

Seems like it would be easier to buy a metric rule than constantly converting. I have rules and tapes in inches, metric, and tenths of an inch; they all come in handy. Earlier my daughter needed a bunch of stuff cut and the parts list was in tenths, 1.83", 1.71", etc. No trouble at all.


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## WoodES (Oct 8, 2013)

Type mm into Google, a conversion website will be the result.


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## 000 (Dec 9, 2015)

I just use 25.4 and divide or multiply depending on which I'm converting. 
I always have my phone with me anyway, so nothing else to carry around or find. Just pull it out and use the calculator app.


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## AlaskaGuy (Jan 29, 2012)

The instructions that came with my Blum under mount drawer slides had both MM and imperial measurement right on the instruction. No conversion necessary.

I do have metric tapes and steel rules and my calipers read both MM and imperial. I can convert either way with a touch of a button.


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## Andybb (Sep 30, 2016)

> Seems like it would be easier to buy a metric rule than constantly converting. I have rules and tapes in inches, metric, and tenths of an inch; they all come in handy. Earlier my daughter needed a bunch of stuff cut and the parts list was in tenths, 1.83", 1.71", etc. No trouble at all.
> 
> - Rick_M


Apologies to the OP for the hijack. I have an architects rule that I haven't used in 30 years and I was a chemistry major so have no problem with the math or conversions. My issue is that I am a 60 year old American curmudgeon and my *brain* is calibrated to imperial. If you tell me it's 37C outside I have no reference but I know what 98F feels like. My table saw fence is in inches, my router lift is in inches as well as almost everything else I measure or cut with so I convert back to inches most of the time. Lumber stores here are starting to measure thicknesses in mm so I do know that 3mm plywood fits in an 1/8th inch groove.

I remember back in the 70's we were going to switch to metric and were ready to bite the bullet but unfortunately it just never happened.

Then there's the Brits. A boxer weighs 12 stone 4 at the weigh in? WTF is that??!  Is a lid still 3 fingers?


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## robscastle (May 13, 2012)

Blum drawer slides and soft close hinges


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## AlaskaGuy (Jan 29, 2012)

I never said a word about Blum Hinges. In fact nobody has except very brief mention by the OP


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## wapakfred (Jul 29, 2011)

> Maybe one day the US will convert to metric but I doubt it.
> 
> - hokieman


Unfortunate, but so true…...we really, really hate change (apparently).


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## Markmh1 (Mar 9, 2017)

I've always used .03937 as a multiplier.

A millimeter is .03937 inches. Punch MM's into your calculator, multiply, and you're done. Remember fractional inches are just a division problem. 13/16 is 13 divided by 16= .8125. .8125 divided by .03937 = 20.67 MM.

If you want to figure in your head and get ballpark, just use 40 thousandths.

We went to the moon in inches.

Mark


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## wormil (Nov 19, 2011)

If I want to convert units, I pick up my phone and say, "Google, convert X to Y." And it spits out an answer quicker than I can open an app or reference chart. I carry it everywhere I go, might as well put the tech to work.


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## AlaskaGuy (Jan 29, 2012)

> If I want to convert units, I pick up my phone and say, "Google, convert X to Y." And it spits out an answer quicker than I can open an app or reference chart. I carry it everywhere I go, might as well put the tech to work.
> 
> - Rick_M


What you going to do when the network is down or the battery gives up or you drop it in the toilet?


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## Bohaiboy (Jun 27, 2013)

I have lived in numerous countries and all but US use metric. Metric is easy, so much easier than imperial. Unfortunately, as Americans, we are always trying to convert from metric back to imperial. For instance, if a cutout calls for 72 mm, we are scratching our heads to try to think how many 1/8 or 1/16th that will be versus taking it as an absolute. If I need to have 72 mm, it is very easy, it is 36 mm, 1/2 is 18 mm and so on. Whereas 72 mm is 2.835", the fractional portion lies somewhere between 13/16 and 7/8" (14/16") But then trying to divide those by 2 or 4 creates additional math headaches.

Think of it this way, what size is your car engine? I bet it is in liters of displacement and no one even considers converting that to cu. in. the way engines used to be. JMTCW.


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## oldnovice (Mar 7, 2009)

Being able to do it correctly, without any aids, only works up to four beers!


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## 000 (Dec 9, 2015)

> I have lived in numerous countries and all but US use metric. Metric is easy, so much easier than imperial. Unfortunately, as Americans, we are always trying to convert from metric back to imperial. For instance, if a cutout calls for 72 mm, we are scratching our heads to try to think how many 1/8 or 1/16th that will be versus taking it as an absolute. If I need to have 72 mm, it is very easy, it is 36 mm, 1/2 is 18 mm and so on. Whereas 72 mm is 2.835", the fractional portion lies somewhere between 13/16 and 7/8" (14/16") But then trying to divide those by 2 or 4 creates additional math headaches.
> 
> Think of it this way, what size is your car engine? I bet it is in liters of displacement and no one even considers converting that to cu. in. the way engines used to be. JMTCW.
> 
> - Bohaiboy


A decimal is still a decimal.
What do you do when the measurement falls somewhere in between 4 and 5mm ?


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## torus (Apr 8, 2017)

> What do you do when the measurement falls somewhere in between 4 and 5mm ?


It is easy - it is 4.5 mm


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## AlaskaGuy (Jan 29, 2012)

> What do you do when the measurement falls somewhere in between 4 and 5mm ?
> 
> It is easy - it is 4.5 mm
> 
> - torus


Well yeah but you have to be able to see those little lines.


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## wormil (Nov 19, 2011)

> What you going to do when the network is down or the battery gives up or you drop it in the toilet?
> - AlaskaGuy


Well I'm not clumsy and I don't let the battery run dead but it is possible the internet could coincidentally go down at that moment and I would have to face the minor inconvenience of manually converting or just use the less familiar system of measurement.

What do you do when the batteries go dead on your digital calipers or you drop them in the toilet?


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## AlaskaGuy (Jan 29, 2012)

> What you going to do when the network is down or the battery gives up or you drop it in the toilet?
> - AlaskaGuy
> 
> Well I m not clumsy and I don t let the battery run dead but it is possible the internet could coincidentally go down at that moment and I would have to face the minor inconvenience of manually converting or just use the less familiar system of measurement.
> ...


I have more than one digital caliper…...and a couple metric tapes and rules. If I can't make it then I go eat some pickled frozen MukTuk

Oh yeah I have a big magnifying glass too. If I just have to get work done I go to cubits


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## wormil (Nov 19, 2011)

> I have more than one digital caliper…...and a couple metric tapes and rules. If I can t make it then I go eat some pickled frozen MukTuk
> 
> Oh yeah I have a big magnifying glass too. If I just have to get work done I go to cubits
> 
> - AlaskaGuy


See, no need to worry.


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## fliming (Feb 23, 2019)

If you need an alternate of this tool you can easily convert your conversions here by simply following this https://mm-to-inches.net


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## Sylvain (Jul 23, 2011)

This week, I made a little dovetail box for my chisels.
I didn't measure anything, using only hand tools.

Using mm comes from metal working/engineering and makes sense in woodworking if you use machines.

If you go shopping for furniture (except maybe in US) dimensions are given in cm (centimeter). {IKEA.US web site shows the two systems.}
Centimeter is what I used at primary school while learning metric system ( commensurate to a school notebook). For me it is concrete; millimeter is somewhat more abstract.

I use cm if I want to design something in wood which needs defined dimensions. Now If I have to install Blum equipment, I will have to use the dimensions given by the instructions, no choice.

When doing scientific calculations, I would not use "1 mm" but "1 E-03 m" because using basic units will prevent magnitude errors.


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## JohnDon (Mar 14, 2015)

I use a cheap plastic caliper (HF sells them for $2). Slide cursor on mm scale, immediately see fractions on other scale; easier to align than double scale rule.


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## GR8HUNTER (Jun 13, 2016)

for the line boring machine we had you had to buy a tape measure in MM to lay out holes cause if your using BLUM this is the easiest way on doing it then stretchers and all work out just right :<)))


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## ArtMann (Mar 1, 2016)

Decimal inches work just as well as the metric system and for the same reasons.


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## xeddog (Mar 2, 2010)

> What do you do when the measurement falls somewhere in between 4 and 5mm ?
> 
> It is easy - it is 4.5 mm
> 
> - torus


Wouldn't that be 4,5mm? I think I would say 4-ish mm

Wayne


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## CWWoodworking (Nov 28, 2017)

I live in a world where millimeters don't exsist.


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## Sam99 (Aug 17, 2019)

Yes, I am using MM to Inches to convert Millimeters to Inches


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## MrRon (Jul 9, 2009)

This metric vs imperial measuring system keeps popping up. I guess it will never be resolved, nor should it. Either system works just fine. I am now retired, but in my past job, I had to work in both systems. I never had a problem doing so. I feel right at home using either system. I prefer the imperial system because that is what I grew up using. If you grew up with the metric system, then that is what you would prefer. Everything I do, is in the imperial decimal system. Even woodworking is done using decimals; fractions are not close enough for the work I do. I know many are not conversant in mathematics, but I am lucky in that mathematics comes as second nature to me. I switch between imperial to metric to decimal without a pause. Decimal equivalents are etched into my brain, so I don't have to refer to charts. If one works with numbers on a continual basis then it becomes second nature.


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## oldnovice (Mar 7, 2009)

How about converting fortnights per furlong?
Pardon me, it's late at night and I am bushed!


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## knockknock (Jun 13, 2012)

I have Inch/Metric rulers and combination squares. I wish rulers came by default with the scales on my GEI MODEL 1086A .


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## MrRon (Jul 9, 2009)

I wonder if Alexa or Echo could be programmed to make instant metric/imperial conversions? You could say "ALEXA convert 6 ounces to grams" or "ALEXA convert 7 inches to millimeters".


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## wormil (Nov 19, 2011)

Google assistant will convert. I don't have Alexa installed to test.


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## RobS888 (May 7, 2013)

> Decimal inches work just as well as the metric system and for the same reasons.
> 
> - ArtMann


I don't know about that, mm being smaller would require less decimal places. In fact many times you wouldn't need a decimal with mm, but do with decimal inch. Why would that matter to me? 12.5mm is easier to remember, notate, and find on a scale than 0.492126 inches.


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## LeeRoyMan (Feb 23, 2019)

convert 1 3/16" to metric.
If your good with rounding up or down to the nearest 1/2 mm than I guess your good with that.
When you know the decimal to fraction equivalents, I don't see a problem no matter what the decimal is.
Number is a number.


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## therealSteveN (Oct 29, 2016)

I see America being a choice country. I never see tools, bits, rulers, pretty much anything sold that you can't also get metric equivalent. I understand that manufacturers use both, and to work on things you may need both, but in the items you make from the ground up, if you like Metric, you can certainly make it metric.


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## Lazyman (Aug 8, 2014)

How about the new The new Metric / Inches unified ruler

One ruler to rule them all. ;-)


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## RichT (Oct 14, 2016)

Going back to the original post-that the OP is converting units for installing Blum hardware, exact conversions aren't needed most of the time. For the drawer slides for instance, one of the measurements is the drawer width relative to the opening and the drawer side thickness. In the literature, they specify both mm and inches. For example, on the 563 undermount if the drawer side is 1/2" the drawer should be the opening width minus 5/8" or 16mm. It doesn't matter that 5/8" isn't exactly 16mm, because it's close enough. In fact that's the case for pretty much all of the measurements. If it says 12mm and all you have is an imperial rule, 1/2" is good enough.

The only time exact placement is needed is for the hinge and adapter plates, and for those, I use drilling templates and jigs. If you are a weekend warrior and install a couple of hinges a year, then use the hardware and an awl to locate your holes. The volume of work I do warrants the jigs and templates.


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## rsneha (May 19, 2020)

I usually use this mm to inches converter


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