How Much Wood to Buy Calculator
Take your project’s total board footage, pick the standard stock size you’ll actually find at the lumberyard, add 10-15% for defects and cutting waste, then divide by that board’s own board-foot count to get exactly how many boards to put in the cart.
Quick Answer
Take your project’s total board footage, pick the standard stock size you’ll actually find at the lumberyard, add 10-15% for defects and cutting waste, then divide by that board’s own board-foot count to get exactly how many boards to put in the cart.
How Much Wood to Buy Calculator
Enter the board feet your project needs and the stock size you plan to buy, and this calculator tells you how many boards to purchase and what they’ll cost.
Enter your values and click calculate.
How to Use This Calculator
Add up board feet for every part of the project (use a board-foot calculator on individual pieces if needed).
Lumberyards sell fixed nominal sizes — matching your plan to an actual available size avoids surprises at checkout.
10% covers clean, select stock; 15% or more is safer for construction-grade or knotty lumber where you’ll cull some boards.
This tells you the actual number of boards to load into the cart, plus how much spare material you’ll end up with.
Formula
Boards to buy = ceil( (Board feet needed x (1 + waste%)) / Board feet per chosen board ). Board feet per board = (Thickness in x Width in x Length ft) / 12.
Board Feet by Common Stock Size
| Nominal size | Board feet |
|---|---|
| 1x4x8 | 2.67 |
| 1x6x8 | 4.00 |
| 2x4x8 | 5.33 |
| 2x4x10 | 6.67 |
| 2x6x8 | 8.00 |
| 2x6x10 | 10.00 |
Common Mistakes to Avoid
- Buying by piece count without checking actual board feet — a 2×6 has almost 50% more wood than a 2×4 of the same length.
- Skipping a defect buffer on rough or construction-grade lumber, then running short after culling knotty or warped boards.
- Forgetting that dimensional lumber’s actual size is smaller than its nominal size (a “2×4” is really 1.5 in x 3.5 in) — this matters for board-foot math using actual, not nominal, dimensions where precision counts.
- Not comparing price per board foot across different stock sizes, which can vary even within the same species and grade.
When the Estimate May Be Wrong
This works best for dimensional softwood lumber sold in fixed nominal sizes. Hardwood is frequently sold as random-width, random-length stock priced per board foot rather than fixed dimensions, so for hardwood projects, use a straight board-foot calculator and expect to buy odd-sized boards rather than clean multiples.
FAQs
How do I convert board feet to number of boards?
Divide your total board feet needed (plus a waste buffer) by the board-foot count of the specific stock size you’re buying, then round up.
How much extra lumber should I buy?
10-15% beyond the bare calculated minimum is typical, more for rough, knotty, or figured stock where you’ll cull some boards.
Is buying bigger boards and ripping them down cheaper than buying to exact size?
Sometimes — compare price per board foot between sizes, since larger dimensional stock is occasionally cheaper per board foot than narrow pre-ripped boards.
Sources and Methodology
Board-foot figures per nominal stock size use the standard board-foot formula (thickness in x width in x length ft / 12) applied to common nominal lumber dimensions as sold at US lumberyards and home centers as of 2026.
