Practical reference calculators

Rules of Thumb

Free, browser-based calculators for the numbers people reach for again and again — organised by discipline. Everything runs entirely on your device: no accounts, no servers, nothing sent anywhere. Pick an area to get started.

Areas
1 tool

Weather

Moist-air physics, humidity, dew point, and the atmosphere's other moving parts.

Psychrometer — humidity state calculator
Open Weather
1 tool

Engineering

Structural and mechanical reference — load, stress, and the standard checks that go with them.

Beam Bench — deflection & stress calculator
Open Engineering
More areas are on the way. Each one gets its own dedicated space — built and added as they're ready.