How to calculate yardage - Handyman Articles

If you are going to pour concrete or fill an area with dirt or rock, you may need to know how many yards of material you will need.  Here is a detailed explanation on how to do it.  If you understand basically how to do it, but just can’t remember the formula, then you can skip to the bottom of the page for the formula.  Otherwise, read this whole article so you understand what the numbers are referring to.  It is easier to do the math when you understand what the numbers mean.

First of all, when we say ‘yard’ or ‘yardage’ we mean one cubic yard.  That is, 1 yard long by 1 yard wide by 1 yard tall.  Volume = length X width X height.  We will use a concrete slab pour for our example.  Let’s say that we need the yardage for a slab that will be 15 feet long by 10 feet wide and 4 inches thick.  First we find the area by multiplying the length times the width.

15 feet X 10 feet = 150 square feet

Now we need to take this number times the height or the thickness.  Our thickness is 4 inches which needs to be converted to feet.  To convert from inches to feet you need to take the 4 inches and divide it by 12 inches.  We use 12 inches because there are 12 inches in one foot.

4 inches / 12 inches = .3333333333 feet or 1/3 of a foot

Now we take the area of 150 square feet times the depth of .3333333333 feet or 1/3 of a foot

150 square feet X .333333333 feet = 49.9999999995 (we’ll round that to 50) cubic feet
Or you can take 150 square feet / 3 (this is the same as 96 X 1/3) = 50 cubic feet

Now we need to convert from cubic feet to cubic yards.  1 yard is equal to 3 feet.  If we convert the length X width X height of one yard into feet we get 3 feet long X 3 feet wide X 3 feet high.

3 feet X 3 feet X 3 feet = 27 cubic feet

Now we need to find how many times 27 cubic feet (or cubic yard) fits into the cubic feet of our concrete pour of 50 cubic feet.

50 cubic feet / 27 cubic feet = 1.8518518518 cubic yards

That is how you figure out yardage.  For a concrete pour you normally have imperfections in the grading that can take up some of your concrete.  You don’t want to run out so make sure you order a little extra.  Most people order 10-15% more than the exact calculations.  If you are using a pump truck you should ask the pump truck company you will be using how much extra to order for the pump truck.  A pump truck will usually waste at least 1/3 of a yard.  Be prepared for this.  It is better to have too much than not have enough. 

Click here for a suggestion on what to do if you have a little concrete left over.

Review

Okay, so here is the review:

Length in feet X width in feet X height in feet = volume in cubic feet
15 X 10 X .3333333333 = 50

Divide the volume in cubic feet by one yard in cubic feet = the volume in cubic yards or yardage
50 / 27 = 1.8518518518

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