Wood movement calculator: how much a board shrinks or swells
Pick the species, the cut and the width, then the moisture content now and later. Get the change in width from the shrinkage values in the USDA Wood Handbook, for tabletops, panels and drawers.
A wide tabletop glued tight to its frame can crack, and a drawer that fits in winter can stick in summer. I wanted a number before cutting. This gives the width change across the grain for a board you choose.
Shrinkage from green to ovendry, by species
| Species | Radial (%) | Tangential (%) | Table |
|---|---|---|---|
| Alder, red | 4.4 | 7.3 | 4–3 |
| Ash, white | 4.9 | 7.8 | 4–3 |
| Basswood, American | 6.6 | 9.3 | 4–3 |
| Beech, American | 5.5 | 11.9 | 4–3 |
| Birch, yellow | 7.3 | 9.5 | 4–3 |
| Caribbean pine (Pinus caribaea) | 6.3 | 7.8 | 4–4 |
| Cedar, western red | 2.4 | 5 | 4–3 |
| Cherry, black | 3.7 | 7.1 | 4–3 |
| Courbaril / jatoba (Hymenaea courbaril) | 4.5 | 8.5 | 4–4 |
| Douglas-fir, coast | 4.8 | 7.6 | 4–3 |
| Hemlock, western | 4.2 | 7.8 | 4–3 |
| Hickory, shagbark | 7 | 10.5 | 4–3 |
| Ipe (Tabebuia spp.) | 6.6 | 8 | 4–4 |
| Iroko (Chlorophora spp.) | 2.8 | 3.8 | 4–4 |
| Mahogany, African (Khaya spp.) | 2.5 | 4.5 | 4–4 |
| Mahogany, true (Swietenia macrophylla) | 3 | 4.1 | 4–4 |
| Maple, red (soft maple) | 4 | 8.2 | 4–3 |
| Maple, sugar (hard maple) | 4.8 | 9.9 | 4–3 |
| Oak, northern red | 4 | 8.6 | 4–3 |
| Oak, white | 5.6 | 10.5 | 4–3 |
| Parana pine (Araucaria angustifolia) | 4 | 7.9 | 4–4 |
| Pau marfim (Balfourodendron riedelianum) | 4.6 | 8.8 | 4–4 |
| Pine, eastern white | 2.1 | 6.1 | 4–3 |
| Pine, loblolly (Pinus taeda) | 4.8 | 7.4 | 4–3 |
| Pine, ponderosa | 3.9 | 6.2 | 4–3 |
| Pine, slash (Pinus elliottii) | 5.4 | 7.6 | 4–3 |
| Purpleheart (Peltogyne spp.) | 3.2 | 6.1 | 4–4 |
| Redwood, young growth | 2.2 | 4.9 | 4–3 |
| Rubberwood (Hevea brasiliensis) | 2.3 | 5.1 | 4–4 |
| Sapele (Entandrophragma cylindricum) | 4.6 | 7.4 | 4–4 |
| Spanish-cedar (Cedrela spp.) | 4.2 | 6.3 | 4–4 |
| Spruce, Sitka | 4.3 | 7.5 | 4–3 |
| Sweetgum | 5.3 | 10.2 | 4–3 |
| Teak (Tectona grandis) | 2.5 | 5.8 | 4–4 |
| Walnut, black | 5.5 | 7.8 | 4–3 |
| Yellow-poplar | 4.6 | 8.2 | 4–3 |
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How it works
Wood shrinks most along the growth rings (tangentially), about half as much across them (radially) and very little along the grain.1 So a plainsawn board moves more in width than a quartersawn one.
The Wood Handbook lists, for each species, the shrinkage from green to ovendry in percent (its Tables 4–3 and 4–4). It also gives a way to estimate shrinkage when great accuracy is not needed: assume shrinkage starts at the fiber saturation point, about 30% moisture content, and that dimensions shrink linearly as moisture drops.1 So shrinkage at moisture x is S₀ × (30 − x) / 30. This page computes the width at both moisture contents from that line and gives you the difference.
The handbook suggests tangential values for plainsawn boards, radial for quartersawn and tangential when you do not know.1 It also warns that individual pieces vary, with a coefficient of variation of about 15%, and probably more in commercial lumber.1 The range shown is ±15% of the result, as a reminder, not a guarantee.
Common questions
Where do I get the two moisture contents?
From a moisture meter, or from the equilibrium moisture calculator on this site with the humidity of your driest and wettest months.
Why are some of the woods I know missing?
I only list species printed in the handbook tables. The imported woods come from world literature and, as the handbook notes, may not be a true species average. Plantation pine from other countries can also differ from the US averages.
Where this comes from
- Samuel V. Glass, Samuel L. Zelinka (USDA Forest Products Laboratory). Moisture relations and physical properties of wood. Wood handbook, chapter 4 (FPL-GTR-190, 2010). US government technical handbook. Samuel V. Glass, Samuel L. Zelinka (USDA Forest Products Laboratory) Consulted 1 Nov 2026.