Calculators for wells, septic and wood heat
Size a pressure tank, pump or septic tank, choose a wood stove, and measure firewood. Each formula comes from a named manufacturer, code or extension source, with a worked example you can check.
Well Pressure Tank Size Calculator
How much drawdown you need, the total tank volume that gives it, and the smallest Amtrol Well-X-Trol model that meets it.
Well Pump Size Calculator (GPM and Total Dynamic Head)
Estimate the flow rate your household needs and the total dynamic head the pump must work against.
Septic Tank Size Calculator (by bedrooms)
Minimum septic tank size and design flow by bedroom count, using Washington State's on-site sewage rule.
Wood Stove Size Calculator (BTU output)
Estimate your heating load and the stove output range to look for on the EPA certification label.
Firewood Cord Calculator (volume and BTU)
Turn a woodpile's measurements into cords, and see how much heat it holds by species.
How Much Firewood Do I Need? (cords per season)
Cords per heating season from your heat need, the species you burn, and your stove's efficiency.