Every appliance-cost calculation needs a rate, and most people enter the wrong one. The advertised "12¢/kWh" is generation only — your bill layers delivery charges, taxes, and riders on top, and the true rate runs 20–40% higher. Honest appliance math starts with bill ÷ kWh.
The bill anatomy
| Line item | Typical share |
|---|---|
| Generation/supply (the advertised rate) | 55–70% |
| Delivery/transmission | 20–30% |
| Taxes and surcharges | 5–15% |
Computing your true rate
- Take the bill total — everything, taxes included.
- Take the kWh used — on the usage line.
- Divide. A $140 bill for 800 kWh is a true rate of 17.5¢ — regardless of the 12¢ headline.
- Enter THAT number in every calculator on this site.
The rate structures that complicate it
- Tiered rates: price per kWh rises with usage tiers — your marginal rate (the last tier) is the honest number for appliance decisions.
- Time-of-use: peak vs off-peak pricing — run the calculator per period for load-shiftable devices (dishwashers, EVs, laundry).
- Demand charges (some commercial plans): price the PEAK draw, not the energy — a different calculation entirely.
Why it matters
The true rate is the denominator of every payback decision on this site: LED paybacks, appliance upgrades, vampire fleets. Understating it by 30% understates every saving by 30% — and tips borderline decisions the wrong way. Compute it once per year (rates move), write it on the meter, and the arithmetic stays honest.