How many boards do I need?
The arithmetic everyone reaches for is total length divided by stock length, and it is wrong in the expensive direction. A part cannot span two boards, so every stick ends with a piece of drop that is only useful if something on your list is shorter than it.
A worked example. Twelve shelf edges at 38 inches, cut from 96 inch stock. Total length is 456 inches, which is 38 linear feet, and 456 divided by 96 is 4.75 - call it five sticks. Now cut it: two 38 inch parts fit on a 96 inch board with room for the blade, three do not (114 inches will not come out of 96). Two parts per board, twelve parts, so you need six boards - one more than the division said, and the extra 20 inches of drop per stick is where the difference went.
That gap grows with awkward lengths. Enter the cut list and your stock length in the linear optimizer and it packs the parts with your kerf, reports how many sticks to buy, and shows where each cut falls so you can mark the boards before the saw is running.
What is a linear foot?
A linear foot is one foot of length measured along the material, with width and thickness ignored entirely. (Rough hardwood is not sold this way - it is priced by volume, which the board foot calculator works out.) Trim, moulding, deck boards, pipe, conduit, bar stock and aluminium extrusion are all normally priced this way.
The consequence catches people at the till: ten linear feet of 1x4 and ten linear feet of 1x12 are both ten linear feet, but they are not the same quantity of wood and never the same price. A price "per linear foot" is only comparable between boards of the same profile.
How to calculate linear feet
Add up the lengths of every piece and, if you measured in inches, divide by 12. That is the whole calculation - no width, no thickness, no area.
Where it stops being useful is buying. Linear footage tells you how much material ends up in the project; it says nothing about how much you must carry out of the yard, because the drop at the end of each stick is usually unusable. For a shopping number you need the packing pass, not the sum.
Linear feet vs board feet vs square feet
| Measure | What it counts | Formula | Sold this way |
|---|---|---|---|
| Linear foot | Length only | total length in inches / 12 | Trim, moulding, deck boards, pipe, bar |
| Board foot | Volume | thickness (in) x width (in) x length (ft) / 12 | Rough hardwood at the sawmill |
| Square foot | Area | width (ft) x length (ft) | Sheet goods, flooring, siding |
A 10 foot 1x6 is 10 linear feet and 5 board feet at the same time - the numbers describe different things about the same board. Rough hardwood is quoted by the board foot because thickness varies; dimensional lumber and trim are quoted by the linear foot because the profile is fixed.
Common stock lengths
| Material | Standard lengths |
|---|---|
| Lumber (2x4, 2x6) | 8 ft, 10 ft, 12 ft, 16 ft |
| Trim and moulding | 8 ft, 12 ft, 16 ft |
| Deck boards | 8 ft, 12 ft, 16 ft |
| Copper pipe | 10 ft, 20 ft |
| Steel bar | 20 ft |
| Aluminium extrusion | 6 ft to 24 ft, varies by profile |
Stock length is a lever, not a constant. The same cut list out of 12 foot boards instead of 8 foot ones can drop the piece count and the total spend at once, and running both numbers takes a few seconds. Longer sticks are also harder to transport, which is a real constraint the calculator cannot see for you.
Kerf and drop, the two things the sum ignores
Every cut turns material into dust. A mitre saw blade takes about 1/8 inch, an abrasive chop saw more, a cold saw less, a shear none at all. Three 32 inch parts do not come out of a 96 inch board once two kerfs are in the way - the third lands at 31 3/4 inches, and if the part has to be 32, the board holds two.
Drop is the other half. A stick that ends with 20 inches left over has not wasted 20 inches if something on your list is 18 inches long - it has produced an offcut. That is why feeding the whole project into one run beats optimising room by room: the short parts fill the ends of the sticks the long parts opened.
Tips for cutting from stock lengths
Cut the long parts first. Not for the maths, which the packer handles, but for the mistakes: a long part cut from a partly used stick is unrecoverable, while a short one can come out of nearly any leftover.
Mark every cut before starting. The plan tells you which parts come off which stick. Marking them all first turns a session of measure-cut-measure into one setup per length.
Mind the ends of bought stock. Lumber ends are often split or out of square, and pipe ends can be burred. If you need a clean end, take a trim cut and tell the calculator the stick is 95 inches rather than 96.
Batch across the project. One run over every part of the same profile consolidates the drop into a few long offcuts instead of a pile of short ones.
FAQ
How many boards do I need?
Total length divided by stock length is the wrong answer, because a part cannot span two boards. Twelve parts of 38 inches out of 96 inch stock come to 456 inches - 4.75 boards by division - but only two parts fit per board, so the real answer is six. Enter your cut list and stock length into the free calculator and it reports the piece count, the cutting plan and the drop.
What is a linear foot?
A linear foot is one foot of length, measured along the material, with width and thickness ignored. Trim, moulding, deck boards, pipe, bar and extrusion are usually priced this way. Ten linear feet of 1x4 and ten linear feet of 1x12 are both ten linear feet - they are not the same amount of wood, or the same price.
How do I calculate linear feet?
Add up the lengths of the pieces and divide by 12 if you measured in inches. There is no width or thickness in the arithmetic. What that number will not tell you is how many sticks to buy, because offcuts shorter than your next part are lost - that is what the cut calculator is for.
What is the difference between linear feet and board feet?
Linear feet measure length only. Board feet measure volume: thickness in inches times width in inches times length in feet, divided by 12. A 10 foot 1x6 is 10 linear feet and 5 board feet. Rough hardwood is sold by the board foot, trim and dimensional lumber by the linear foot.
Does the calculator account for the saw kerf?
Yes. Every cut removes material - about 1/8 inch on a mitre saw, more on an abrasive chop saw, near zero on a shear. Set your blade's kerf and the plan subtracts it between parts, which is often what turns a stick that looks like it holds three parts into one that holds two.
Is the linear cut calculator free?
Yes - free with no part caps, no cooldowns and no card. The first optimization needs no signup; a free account is only needed to save projects to the cloud.