Enter your numbers
Use metered usage, your rate in cents per kWh, fixed fees, equipment wattage, and run hours.
How to use the numbers
Every result starts with an assumption.
WattWise turns explicit usage and rate assumptions into a first-pass cost screen. The method is simple: show the inputs, define the output, disclose the evidence boundary, and point to the next verification step.
Why this method exists
A calculator should make uncertainty easier to inspect, not make a decision for you.
Electricity estimates are only as credible as the usage and rate assumptions behind them. This site is designed to help you identify those assumptions early, compare scenarios consistently, and carry the important questions into your utility tariff, meter data, and equipment review.
The estimation flow
Inputs in. Formulas visible. Your tariff next.
Read the output
The calculators show labeled outputs such as monthly bill, annual cost, effective rate, payback years, and lifetime savings.
Verify what moves it
Replace broad baselines with your current tariff sheet, meter history, and equipment nameplate data.
Output definitions
Know what each number is measuring.
Monthly bill
Modeled energy cost plus fixed fees for one month of usage.
Annual cost
The modeled twelve-month total at your usage and rate.
Effective rate
Monthly bill relative to the modeled property value or purchase price.
Payback period
Net installed cost divided by first-year bill savings, for solar and efficiency upgrades.
Before you rely on a result
Replace the baseline with evidence from your actual tariff and meter.
Property
Tariff sheets, rate riders, fixed customer charges, and twelve months of metered kWh.
Financing
For solar: net cost after credits, production estimates, degradation, loan terms, and inverter replacement.
Local rules
For utilities: time-of-use windows, tier thresholds, demand charges, and net metering rules.
Rate baselines are dated starting points, not live utility feeds. Calculator results are screening outputs, not utility bills, quotes, or guarantees.
Editorial evidence standard
Trust comes from showing where the information ends.
Source and date
Rate tables should show their data year and source context. A dated baseline is not presented as a live utility feed.
Method and limits
Definitions, modeled inputs, warnings, and professional-verification boundaries are kept visible so a reader can judge whether an output fits the question.
Corrections and review
If you find an incorrect definition, broken calculation, unclear source, or stale observation, send the page URL and the issue through Contact so it can be reviewed.