Tools
Calculators for the numbers that are awkward to do in your head. Every figure comes from a page in the library, and each tool links to it.
- Bleach dosingMaking water drinkable, or disinfecting a tank. Two very different strengths.
- Water storageHow much a household needs standing by, in containers you can actually buy.
- Calorie daysHow long the food in the house lasts, or how much a given stretch needs.
- Rainwater yieldWhat your own roof collects in a year. Usually far more than people expect.
- Solar sizingBattery, panel and controller, sized against the season you actually need it in.
If these will not run
Each tool also states its formula and a worked example in plain text, so the sum can be done on paper if the calculator does not work on your device. Nothing here is only available as a calculator.