Timber (Lumber) sizes metric compared against dimensional

Submitted by deannaf on Fri, 09/03/2010 - 15:27

The thing that I have found a bit challenging when determining which timber to use has been the sizing.

Below is what I have been substituting for the dimensional lumber sizes noted in plans, I am live in Adelaide, Australia. I just wanted to run these past others here to see what they thought, are these roughly the timber sizes you have been using. It would be comforting to know I have been on the right track.


1x4 = 19mm x 90mm

1x5 = 19mm x 120mm

1x6 = 19mm x 140mm

1x8 = 19mm x 190mm

1x10 = 19mm x 240mm


2x4 = 35mm x 90mm

2x5 = 35mm x 120mm

2x6 = 35mm x 140mm

2x8 = 35mm x 190mm

2x10 = 35mm x 240mm


Would love others input.





Sat, 09/04/2010 - 03:09

Hi Deanna,

Your list is pretty much what I've found the sizes to be - but I've been having trouble finding anything bigger than the 35mm x 120mm that isn't treated pine. I've only been to Bunnings, but I wondered whether it was because I'm in a regional area and there is less choice. I've always had a too-energetic 3yo with me to stop and get help from the staff, but I'm planning to do that soon.

When I made a bigger kids picnic table, I was able to use the 35mm x 90mm, but couldn't find anything that seemed equivalent to the 2x6s needed for the top and so had to use 19mm x 140mm. It does look a little out of proportion, but has so far survived being climbed on and jumped off.




Sat, 09/04/2010 - 13:44

Hi Vanessa,

Thanks for confirming what I had listed is what you found. I must be lucky because I can get up to the 35mm x 240mm at Bunnings here in Adelaide, I have three Bunnings that I can go to around me to get my wood one of them has better a selection than the other 2, I would love to have access to stores the other guys on this site have access to.

I have two kids and I hear what you are saying about going to get wood with them in tow, I wait until I can go by myself so I can focus on what it is that I need.

Glad your picnic table worked out well. I am just finishing up with the Farmhouse bed (double) for my daughter. I am really pleased with how it is coming out, I even got out my router and gave that a go. Next on my building list is a workbench and then onto bunk bed for my son.


Deanna Wink


Mon, 09/06/2010 - 18:12

Thanks for this list, Deanna! I've been wanting to start on a few projects from Ana's plans, but have been a bit nervous about converting the dimensions. Maybe I can make a start on the calculations now. Until I moved last week, I've been living too far from a Bunnings to be able to just pop in and look at the dimensions of timber they sell. (I'm a kiwi, but I live in QLD)


Tue, 09/21/2010 - 10:20

That doesn't look to different from what you can get over here in Germany, too.

Here is a neat little list of the actual lumer sizes. Maybe that helps, too.


Wed, 09/29/2010 - 10:51

Ahaaa!!! I'm another kiwi, in the south island... But living too far away from Bunnings, (have mitre 10 and stuff like that, but priceyyyyyyy!) am off to a town that has bunnings in next few weeks, hopefully Ana has done the craft table plans by then, so I can get my stuff from there, since I'll be taking the truck over with me anyway!
WOHOOOO Thanks for this guys :)


Tue, 11/09/2010 - 03:47

Thank-you Deana - this is a big help! :) I was able to finish my first project successfully but it was a little difficult converting back and forth between inches and mm taking into account the fact that in Australia 19mm is actually 19mm but 1 inch is not 1 inch when it comes to lumber :)


Mon, 11/15/2010 - 22:33

I agree AHUVAS

I was able to finish my first project successfully but it was a little
difficult converting back and forth between inches and mm taking into
account the fact that in Australia 19mm is actually 19mm but 1 inch is
not 1 inch when it comes to lumber :)


What I do is when I get my timber home from that point I then measure everything out in inches that way I can check against Anas plans, some need tweeking others you can get away with. Its all a challenge but once you can look at the fabulous piece of furniture you made it makes it all worth while.


LaurieP (not verified)

Thu, 07/14/2011 - 10:59

Have you had trouble finding sizes in Germany that were close to the plans on here? For example, I can't find any equivalents for 2x4- I know it's 38mmx89mm, but both stores I looked at didn't carry that size.

LaurieP (not verified)

Thu, 07/14/2011 - 11:01

Have you had trouble finding sizes in Germany that were close to the plans on here? For example, I can't find any equivalents for 2x4- I know it's 38mmx89mm, but both stores I looked at didn't carry that size or anywhere close to that.


Thu, 03/17/2011 - 12:42

Great to hear others are confused when buying timber in metric. i live in Ireland and I converted everything into mm and went to the diy stores to find that we dont seem to do any of the sizes i needed. i went to a lumber merchant, but it worked out very expensive ($370) for the lumber alone, so I am now hunting to see how i can tweek the plans for the wood i can find. I want to make the farmouse bed in a twin size, but as this is my 1st creation, I think I have bitten off more than i can chew.



Sun, 03/20/2011 - 00:45

I'm an American living in England, and the metric system is killing me! lol And I can't find the size selection I need here either. If anyone happens to know of a good lumber store here, please let me know!  

Sorby (not verified)

Fri, 06/24/2011 - 07:07

Hi all, fellow Australian here.
Deanna, I hate to tell you this but your measurements are off.

In woodworking, when you measure you do so with unplaned, untreated wood. When it's treated (as most often the wood we buy is) then this size shrinks somewhat, usually by about a half inch. [Ana does mention this on this site too]. So your following measurements are actually:

1x3 = 19mm x 38mm

2x3 = 38mm x 64mm

2x2 = 38mm x 38mm

3x3 = 64mm x 64mm

4 x 4 = 89mm x 89mm

If you need further assistance with measurements, you can find easy reference in any carpentry book in Dymocks (now that Borders has closed) or library.

However, all Australian carpentry tools are two sided: one with the metric system (ours) and the other with the imperial (theirs) so, really, you can use the American plans without issue. Bunnings cut to both systems too.

Hope this helps.

LaurieP (not verified)

Thu, 07/14/2011 - 10:53

I visited two local home improvement store here in Germany and wrote down all the wood sizes available. At one store, I could get 18mm, 24mm, and 28mm lengths and only 38x58. At the other store I could get 17mm, 22mm, only 34x54. Also the widths seem to have no consistency- for example, there's 18x35, 18x43, 18x95, but then 28x45, 28x146, 38x58. I built the farmhouse bed but made several modifications. Buying wood has been quite complicated for this new woodworker. Could anyone explain why the odd sizes? I see there's some Germany folks on here- I went to Toom and Praktiker.


Thu, 09/19/2013 - 12:18

I noticed the same thing in Hornbach. From what I understand, the odd sizes are because wood is used for small framing or projects; concrete blocks and cement are used to frame buildings instead of wood like in the US. Although I was able to get 44x94mm in 2.5 meter lengths - almost exactly an American 2x4 though very expensive. The 2x4s and 1x#'s were in the furniture wood section. The closest to a 2x4 in use and price here is something like a 40x60mm.


Fri, 07/15/2011 - 07:23

Hi Sorby thanks for your comments.

In my post I was referring to what you would actually buy in store at Bunnings. Bunnings for example do not have it in store at 38mm they have it as 35mm. As Bunnings is the most popular place to purchase wood this is why I referenced it like I did as to avoid confusion for other Aussies.

My posts was showing if I walked into the store now and had to buy wood I would by a 35 x 90 for a 2x4. When you state a 1x3 = 19mm x 64mm you cant go into Bunnings and buy that, you buy a 19mm x 70mm because that is what they sell.

There are many references online to show the actual sizing this link is great http://mistupid.com/homeimpr/lumber.htm so no need to buy books.

I have successfully build a number of large furniture items based on Ana's plans with the timber sizes I mentioned.


Sun, 04/08/2012 - 02:02

omg this is very confusing, this is my first go so im doing all of my homework, i think i might stick with inches for now until i get to know the wood.


Sun, 04/08/2012 - 02:43

Okay i think i might have worked it out, please correct me.
this is my cut list.......
2-1x12@35 1/4" = 19mm X 290mm X 890mm
1-1x12@17" = 19mm X 290mm X 430mm
1-1X12@15 1/2" = 19mm X 290 X 390
3-1x10@15 1/2" = 19mm X 240mm X 390mm
1-1x2@15 1/2" =19mm X 38mm X 390mm
2-1x8@32 3/4" = 19mm X 190mm X 830mm
17"x36" ply wood = 430mm X 910mm


Jaola (not verified)

Wed, 12/05/2012 - 11:17

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Wed, 12/12/2012 - 09:48

Here is the correct conversion sizes for lumber

1x2=3/4" x 1 1/2" =19mm x 38mm
1x3=3/4" x 2 1/2" =19mm x 64mm
1x4=3/4" x 3 1/2" =19mm x 89mm
1x5=3/4" x 4 1/2" =19mm x 114mm
1x6=3/4" x 5 1/2" =19mm x 140mm
1x7=3/4" x 6 1/4" =19mm x 159mm
1x8=3/4" x 7 1/4" =19mm x 184mm
1x10=3/4" x 9 1/4"=19mm x 235mm
1x12=3/4" x 11 1/4"=19mm x 286mm
1 1/4x4= 1" x 3 1/2"=25mm x 89mm
1 1/4x6=1" x 5 1/2"=25mmx140mm
1 1/4x8=1" x 7 1/4"=25mm x 184mm
1 1/4x10=1" x 9 1/4"=25mm x 235mm
1 1/4x12=1" x 11 1/4"=25mm x 286mm
1 1/2x4=1 1/4" x 3 1/2"=32mm x 89mm
1 1/2x6=1 1/4" x 5 1/2"=32mm x 140mm
1 1/2x8=1 1/4" x 7 1/4"=32mm x 184mm
1 1/2x10=1 1/4" x 9 1/4"=32mm x 235mm
1 1/2x12=1/1/4" x 11 1/4"=32mm x 286mm
2x4=1 1/2" x 3 1/2"=38mm x 89mm
2x6= 1 1/2" x 5 1/2"=38mm x 140mm
2x8=1 1/2" x 7 1/4"=38mm x 184mm
2x10=1 1/2" x 9 1/4"=38mm x 235mm
2x12=1 1/2" x 11 1/4"=38mm x 286mm
3x6=2 1/2" x 5 1/2" =64mm x 140mm
4x4=3 1/2" x 3 1/2"=89mm x 89mm
4x6=3 1/3" x 5 1/2"=89mm x 140mm

I took this right out of Black & Decker's "Complete guide to easy woodworking projects". I hope this helps anyone that needs.


Thu, 09/19/2013 - 12:12

Based on my recent experience, I picked up some 2x4's for the fancy X table from the local Hornbach (German version of Home Depot). They were sized 44mmx94mm and 2500mm long. Just slightly larger than an American 2"x4"x8' but with the same ratios. The perfect size for a good stout table, but they were very expensive! $12USD per piece!


Wed, 06/11/2014 - 04:29

I gave up al together trying to convert the imperial to metric as I found that most of the time here in South Africa you cannot get the exact size of wood if you do the conversion. I use a CAD application to create the 3D model and from there generate the drawings. I use the plans as more of an idea and make my own plans according to that.

darren griffiths

Thu, 12/11/2014 - 07:09

I have been making lots of furn with Norwegian pine its so much better than south african pine and i bye it dirt cheap from the docks in durban sa but the sizes above look correct eish still soooooo much to learn


Sat, 03/21/2015 - 17:45

When converting lumber sizes the nominal dimensions (2x) or (4x) should NOT be converted, rather the actual sizes like 1.5"x3.5" should be soft converted to 38x89mm.

2x4 = 38x89mm
2x6 = 38x140mm
2x8 = 38x184mm
2x10 = 38x235mm
2x12 = 38x286mm

Soft vs. Hard conversion - soft conversion is simply converting inch-pound units to the nearest equivalent metric unit. Panel products for example are typically 4'x8' which would convert to 1220x2440mm. Hard conversion is when the metric units are rounded to a rational unit. In the preceding example hard conversion for panels would be 1200x2400.

To convert from board feet to cubic meters; according to ASTM E380, multiply board feet by 0.002359737.