Wood Drying (Turning) Calculator

The starting point for this estimate is the well-known woodturner's rule of thumb that green wood air-dries at roughly one year per inch of thickness, which the calculator applies directly (wall thickness × 12 months) before layering on the factors that actually change from bowl to bowl. Denser woods hold more water and dry more slowly, so a density factor scales the baseline from 0.7× for light woods like pine up to 1.8× for very dense species like ipe or ebony. Ambient humidity matters too — a humidity factor of 0.5 plus the relative humidity fraction means a damp basement measurably slows evaporation compared to a dry, airy shop. Sealing the end grain with wax or Anchorseal reduces cracking by slowing moisture loss at the end grain specifically, but that same slowdown costs roughly 20% more total drying time — a real tradeoff, not a free win.

Choosing a dehumidifier kiln or conventional kiln instead of open-air drying multiplies the base time down by 5× or 10× respectively, since forced airflow and controlled humidity pull moisture out far faster than ambient conditions alone. The crack-risk score folds wall thickness, density, and whether the end grain is sealed into a 1-5 rating, since thick, dense, unsealed pieces are the ones most likely to check or split as they dry unevenly. The water-loss figure is a rough estimate built from an approximated bowl-wall volume and typical green-to-target moisture contents by density class — useful for gauging expected weight change, not a precise mass balance.