Tools
Calculators that show their working
Every tool here answers in both unit systems, prints the formula it used, and can be linked with your numbers already filled in. Where a figure is not published anywhere reputable, it says so instead of guessing.
DC wire size
LiveSize cable by voltage drop, then check it against ampacity. Returns the AWG size and the nearest stocked metric size as separate answers.
Plywood cut list
LiveNest parts onto sheets with a real kerf allowance, and compare the sheet count across US, UK, EU, Australian and Baltic birch stock. Guillotine cuts only, so every nest is cuttable.
Battery bank sizing
LiveDaily draw to the capacity you actually buy, with honest depth of discharge per chemistry, temperature derate and the Peukert effect.
Fuse and breaker sizing
PlannedProtect the cable, not the load. Sized from conductor ampacity with the derates applied.
Inverter sizing
PlannedContinuous and surge demand from an appliance list, with the DC-side current it implies.