Air-Dry Lumber Time Calculator

The Classic Rule of Thumb

The most widely cited guideline is one year of air drying per inch of board thickness for hardwoods, and about six months per inch for softwoods. This assumes drying from green (roughly 30 to 40% moisture content) down to air-dry (12 to 15%), stacked with stickers in a covered outdoor location.

This is a rough approximation. Actual drying time depends heavily on species density, board width, local climate, and stack management.

Why Moisture Content Matters

Wood moves with changes in moisture. Furniture built from under-dried lumber will crack, warp, and open at joints as it keeps drying indoors after you finish it.

Wood does not dry to whatever number you pick. It dries to equilibrium with the air around it, and then stops. That is the single most important thing on this page. An outdoor covered stack settles at 12 to 15% in most temperate climates and will sit there for a decade without going lower. An unheated barn is barely different. A heated shop or spare room is much drier, around 6 to 8%, which is exactly what indoor furniture needs.

So the sequence for furniture stock is: air dry outside until it stalls, then bring it inside stickered for another six to eight weeks to finish. The calculator below applies your location’s floor rather than pretending an outdoor stack can hit 6%.

Species Differences

Dense, slow-growing hardwoods like hickory, white oak, and hard maple take longer to dry than lighter species. Softwoods like pine, cedar, and spruce dry quickly. Very dense tropical hardwoods (ipe, teak) can take 2 to 3 years per inch.

Location Factors

Outdoor covered stacking (under a shed roof, good airflow) is the baseline. An indoor unheated building speeds things up slightly by reducing rain wetting cycles. A heated indoor space speeds drying significantly but requires careful monitoring to prevent case hardening, where the surface dries too fast and traps moisture inside.

Sticker Spacing

For best results, use dry stickers (typically 3/4 by 1-1/2 in) spaced 12 to 18 inches apart. Weight or strap the top of the stack to reduce cupping. Align stickers vertically above each other in the stack. Good airflow across all faces is more important than any single rule.