SHED FLOOR CALCULATOR

How many 2×4s for a 10×12 shed floor

You need 12 2×4s if everything is cut from 12-foot stock. Splitting the stock gives 2 12-foot boards for the rims plus 10 10-foot boards for the joists, 12 in all.

Layout assumptions

Two 12-foot rim boards run along the 12-foot sides. Floor joists run the 10-foot direction between them at 16 inches on center: 144 / 16 = 9 spaces, so 10 joists including the two end joists. Each joist is 120 - 2 × 1.5 = 117 inches, using the 1.5 inch actual thickness of a nominal 2×4 rim board.

This counts boards for the layout only. It does not check that 2×4 joists are adequate for a 10-foot span or your floor load, and it excludes blocking, sheathing, and skids. Check span tables, your shed plans, and local code first.

All 12-foot boards (144 in): cut assignments

All 12-foot boards (144 in): cut assignments
Board	Parts	Cut lengths	Remaining offcut
1	Rim board	144 in	0 in
2	Rim board	144 in	0 in
3	Floor joist	117 in	26.875 in
4	Floor joist	117 in	26.875 in
5	Floor joist	117 in	26.875 in
6	Floor joist	117 in	26.875 in
7	Floor joist	117 in	26.875 in
8	Floor joist	117 in	26.875 in
9	Floor joist	117 in	26.875 in
10	Floor joist	117 in	26.875 in
11	Floor joist	117 in	26.875 in
12	Floor joist	117 in	26.875 in

12 boards, 84.4% of the wood used, 268.75 in of offcut.

Rim boards on 12-foot stock: cut assignments

Rim boards on 12-foot stock: cut assignments
Board	Parts	Cut lengths	Remaining offcut
1	Rim board	144 in	0 in
2	Rim board	144 in	0 in

2 boards, 100% of the wood used, 0 in of offcut.

Joists on 10-foot boards (120 in): cut assignments

Joists on 10-foot boards (120 in): cut assignments
Board	Parts	Cut lengths	Remaining offcut
1	Floor joist	117 in	2.875 in
2	Floor joist	117 in	2.875 in
3	Floor joist	117 in	2.875 in
4	Floor joist	117 in	2.875 in
5	Floor joist	117 in	2.875 in
6	Floor joist	117 in	2.875 in
7	Floor joist	117 in	2.875 in
8	Floor joist	117 in	2.875 in
9	Floor joist	117 in	2.875 in
10	Floor joist	117 in	2.875 in

10 boards, 97.5% of the wood used, 28.75 in of offcut.

Load this layout in the planner ↗