Project Planning
Wood Acclimation Timeline Estimator
Estimate how long your lumber should sit in the shop before milling — based on species, board thickness, and moisture differential.
Calculator
8 = most US interiors; 12 = humid climates.
Slow / Medium / Fast
What makes this different
Most 'how long to acclimate' answers are vague ('a week or two'). This one uses the FPL moisture-equilibrium rule of thumb: 1 in of thickness per week of acclimation, plus an adjustment for the initial moisture differential between lumber and shop EMC.
Who it's for & when to use it
Planning a project timeline; deciding whether to kiln-dry lumber on-site; avoiding post-build warping.
How to use
- Enter the dimensions of your material or the parameters of your project.
- Adjust the optional knobs (waste factor, kerf, planer allowance) to match your shop practice.
- Click Calculate and read the output. Use the per-item breakdown for ordering, the totals for budgeting.
- Compare the result to your lumber yard's quote — the effective $/BF column is the apples-to-apples number.
Formula: Weeks ≈ thickness × 1.0 (medium species). Slower species (walnut) add 30 %; faster (poplar) subtract 20 %.
Notes & tips from the shop
- Sticker the lumber — without spacers, the middle of the pile won't equilibrate.
- Aim for the lumber's MC to be within 2 % of the shop's EMC, not just 'dry'.
- For furniture that lives in a heated home, target 6–8 % MC. For outdoor projects, 12–15 %.
Frequently asked questions
What if I'm in a hurry?
Buy lumber already kiln-dried to your shop's MC. Don't try to shortcut the acclimation of green lumber.
Why is my walnut still moving after a month?
Walnut is slow to equilibrate and is sensitive to MC swings. Allow 4–6 weeks for 8/4 stock.
Can I kiln-dry lumber in my shop?
Not effectively — a dehumidifier kiln takes weeks for 4/4 and is a side project in its own right. For most hobbyists, buy KD.
Limitations
Single formula based on FPL guidance. Actual equilibration depends on shop humidity stability.
All calculations happen in your browser — nothing you type is sent to a server.