Electricity Cost Calculator
Once you know how many kilowatt-hours something uses, the last step is turning that into an actual dollar (or local currency) figure — which sounds simple, but real electricity billing has more moving parts than "kWh × flat rate," especially with tiered pricing, time-of-use rates, and fixed charges layered on top of usage.
The Basic Formula
For a flat-rate plan, this is genuinely that simple. A 30 kWh/day household on a flat $0.15/kWh rate spends $4.50/day, or roughly $135/month, purely on usage (before any fixed charges).
Why Your Real Bill Rarely Matches This Simple Math
- Tiered pricing: Many utilities charge a lower rate for the first block of usage each month, then a higher rate once you cross a threshold (e.g., $0.12/kWh for the first 500 kWh, $0.18/kWh beyond that). If you're near a tier boundary, small usage changes can have an outsized cost impact.
- Time-of-use (TOU) rates: Rates that vary by time of day — often cheaper overnight, more expensive during afternoon/evening peak demand hours. Running a dishwasher or charging an EV during a peak window can cost meaningfully more per kWh than the exact same usage shifted a few hours later.
- Fixed charges: A flat monthly connection/service fee that applies regardless of usage — this doesn't scale with kWh at all, so very low-usage households often see a higher effective $/kWh than the posted rate suggests, because the fixed fee is spread across fewer units.
- Demand charges (commercial/industrial): As covered in the main kW to kWh guide, larger customers often pay a separate charge based on their single highest 15-30 minute demand peak in the month, entirely independent of total kWh consumed.
Worked Example — Tiered Rate
A household using 700 kWh in a month, on a tiered plan: $0.12/kWh for the first 500 kWh, $0.18/kWh beyond.
Notice the average cost per kWh here works out to $96 ÷ 700 = $0.137/kWh — different from either posted tier rate, which is exactly why a flat "rate × total kWh" estimate can mislead once tiers are involved.
How to Find Your Actual Rate Structure
Your utility bill (or online account) will specify whether you're on a flat, tiered, or time-of-use plan, and list the exact rate(s) and any fixed charges. If you're estimating future costs (a new appliance, an EV, a solar system), pull your actual current rate structure rather than assuming a flat national average — rates vary enormously by region and utility.
Frequently Asked
Why is my cost per kWh higher than the rate my utility advertises?
Almost always the fixed monthly service charge, spread across your total usage — this effect is largest for low-usage households and shrinks as a percentage of the bill as usage increases.
Does time-of-use pricing actually save money?
It can, if you're able to shift flexible usage (EV charging, laundry, dishwashing) into off-peak windows — but it can cost more than a flat rate if your usage is concentrated during peak hours and you can't shift it.
Where do I find region-specific rates?
See the regional electricity rates directory for current typical rates by region.
For the underlying energy calculation before applying cost, see the main kW to kWh calculator.
Founder & Lead Renewable Energy Specialist
Abdul Rehman is a Renewable Energy Consultant and Solar Systems Specialist. He built kwtokwh.com to provide transparent, accessible calculation tools that help homeowners, electricians, and facility engineers accurately convert electrical power (kW) into billed energy consumption (kWh) calibrated against NIST and IEC metrology standards.