Residential electricity · transparent planning tools
Every number on this site shows its own arithmetic.
Six calculators share one rate source. Change an assumption and the result, formula, and source ledger move with it.
Calculator directory
Frequently asked questions
Where do the electricity rates come from?
Rates are ingested from public sources — EIA retail sales data, published utility tariffs, and the OpenEI Utility Rate Database — then matched to your location. When there's no exact match, Energy Cost Checker falls back to a regional or national average and marks the result as approximate instead of guessing a plan.
Can I use my own rate instead of the estimate?
Yes. Every calculator has an editable rate field. Changing it recalculates the result immediately with the same formula the estimate used, so you can drop in the number straight off your bill.
Do you store what I calculate?
Energy Cost Checker has no accounts, so your inputs aren't tied to an identity. Calculations are sent to the API to produce a result and aren't retained beyond that request — except when you explicitly create a share link, which is anonymous and expires on its own.
Why show the arithmetic instead of just the answer?
Because a number you can't check isn't useful for a decision. Every calculator shows its formula and source next to the result, so you can verify it or swap in your own assumptions.