Solar & EV calculators for US
Five calculators, one page each, with USD defaults. Every default carries its source and date on the field itself, every field is editable, and every page shows the arithmetic it uses plus the things it cannot see. We sell no hardware and take no installer commission, so there is nothing here nudging you towards a bigger system.
6 inputs across these calculators ship blank on purpose. No source we can cite publishes them for US — generation per installed kW is the big one — so rather than pre-fill a plausible number, the calculators wait for yours and print nothing until they have it. Each page says exactly which figures are missing and why.
Rates carry their own dates: US tariffs and pump prices move on their own schedules, so a single site-wide review date would be misleading. See how we verify a number before we print it.
Solar system size calculator
Turn your monthly kWh into a kW system size and a cost band built on Berkeley Lab’s medians. Bring one number: what a kW produces on your roof.
EV vs gas running-cost calculator
Gas at the pump against electricity at home, both from EIA’s own weekly and monthly series. The one calculator here with no blanks.
Panels needed to charge an EV or e-bike
Panels needed to cover your daily miles. Bring the daily kWh one panel makes where you live — PVWatts gives it in a minute.
Solar battery payback calculator
Whether storage pays on arbitrage. Needs your state’s export rate and your quoted battery price — neither exists as a national number.
Net metering vs net billing calculator
What self-consumption is worth against export, once you know your state’s rules. Two inputs are yours; the import rate is EIA’s.
Why there are only five
Because five is how many we can stand behind. Each one is wired to a figure someone else published — the utility’s own tariff, the month’s announced pump price, a dated listing in our US price survey — so you can check every default rather than trust it. Where nobody published the number a calculator needs, we say so on the page and leave the field empty instead of filling it with something that would look identical to a verified figure. Start with the US guides if you want the reasoning behind a rate before you use it.