Electricity Cost Calculator

Estimate the running cost of any appliance — pick a typical appliance or enter its wattage, set how long it runs, and get daily, monthly and yearly cost. Free, instant, no signup.

W
% capacity
hours/day
per kWh
Formula: Cost/day = (watts × capacity% ÷ 1000) × hours/day × price per kWh

How to use the Electricity Cost Calculator

  1. Enter your values. Fill in the fields with your numbers.
  2. Calculate. Press Calculate to run the electricity cost calculator.
  3. Use the result. Copy the result or try a related tool next.

Why use our Electricity Cost Calculator

Instant results. Enter your figures and the electricity cost calculator returns an answer in seconds.
Free & private. Runs in your browser — no signup, and nothing is sent to a server.
Accurate. Uses standard formulas so you can rely on the numbers.

Free to use — premium coming soon

FREE
  • Unlimited calculations
  • Instant results
  • No signup
PREMIUM
  • Remove ads
  • Save & compare scenarios
  • Export results

About the Electricity Cost Calculator

The Electricity Cost Calculator turns an appliance's power rating and how long you run it into a real money figure: cost per hour, day, month, and year. You enter three things you can find without an engineering degree: the device's wattage, the hours it runs, and the price your utility charges per kilowatt-hour (kWh). It then does the unit-juggling that trips most people up, converting watts to kilowatts and multiplying out the time and rate so you don't have to keep dividing by 1,000 in your head. It works for anything that plugs in, from a 5W phone charger to a 3,000W electric water heater.

Reach for this tool when you're trying to pin down where your bill actually goes. Common moments: deciding whether an old fridge or that space heater is worth keeping, sizing the savings before buying an energy-efficient replacement, settling a household argument over the cost of leaving lights or the AC on, or estimating the running cost of a new gaming PC, grow light, aquarium pump, or EV charger. It's equally useful for landlords splitting bills, small workshops costing out machinery, and anyone on a time-of-use plan checking what a high-draw appliance adds per session.

The math is the standard utility-billing formula: kilowatt-hours equal power (in kW) times hours, and cost equals kWh times your rate. So a 1,500W space heater run 8 hours a day at $0.17/kWh uses 12 kWh daily and costs about $2.04 a day, roughly $61 a month. If you only know amps and volts from the nameplate, multiply them (Watts = Volts x Amps) to get wattage first. Most US outlets supply 120 volts; large appliances like dryers and ranges use 240 volts.

Accuracy depends on your inputs, not the arithmetic. A device's listed wattage is its maximum draw, so motors, fridges, and anything that cycles on and off will use less on average than a flat-out estimate suggests, while standby or phantom loads mean many electronics keep sipping power even when 'off.' For the truest rate, copy the price per kWh straight off your bill, and add any per-kWh delivery or supply charges. Everything is computed locally in your browser, so your usage figures and bill details are never uploaded or stored anywhere.

Frequently asked questions

What electricity rate should I enter?

Use the price per kWh printed on your most recent utility bill, since rates vary widely by location. As a rough US reference, the residential average is around 17 cents per kWh, but real prices range from about 12 cents in some states to over 40 cents in Hawaii.

How do I find an appliance's wattage if it isn't labeled?

Check the nameplate, sticker, or manual first. If only amps and volts are listed, multiply them: Watts = Volts x Amps. A device drawing 5 amps on a 120-volt outlet uses 600 watts.

Why is my real bill higher than the calculator's estimate?

The calculator uses the appliance's rated (maximum) wattage and the hours you enter, but bills also include standby/phantom loads, appliances that cycle on and off, and per-kWh delivery, supply, and tax charges that may not be in your headline rate.

Does the calculator work for 240-volt appliances like dryers and ovens?

Yes. Just enter the total wattage of the appliance; the voltage doesn't need to be entered separately. If you only have amps, multiply by 240 (instead of 120) to get the wattage for those larger appliances.

How can I lower the cost a high-wattage device adds?

Run it for fewer hours, switch to a more efficient model, or shift use to off-peak times if you're on a time-of-use plan. For electronics that draw standby power, unplugging them or using a switchable power strip eliminates phantom load.

From our blog

How the Army One-Site Tape Test Works and How to Estimate Your Score

By the Super Simple Digital Tools Team · Updated June 2026

The Army Body Composition Program exists to keep soldiers within a healthy body composition range, and in 2024 it moved to a simpler way of measuring it. Where the old method required taping multiple sites and applying log-based equations, the current one-site test asks for just your body weight and the circumference of your abdomen. That change makes the assessment faster, more consistent between graders, and easy to replicate at home, which is exactly what this calculator does.

The process starts with a screening, not a tape. Each soldier is first checked against a height and weight table for their age and sex. If you fall at or under the maximum screening weight for your height, you meet the standard and no tape test is needed. Only when you exceed that weight does the abdominal measurement come into play to determine your body fat percentage, so knowing your number in advance tells you whether the tape will ever come out.

Taking the measurement correctly matters more than people expect. Use a flexible tape that does not stretch, remove belts and bulky clothing, and stand tall with feet about hip-width apart. Place the tape at the level of your navel, keep it horizontal all the way around, and snug it against the skin without compressing the tissue. Read it at the end of a relaxed breath out. Because a single reading can be off, the Army takes three and averages them to the nearest half inch.

Once you have weight and abdomen in hand, the formula does the rest. Men and women use different equations because body fat distributes differently, but both depend only on those two inputs. Plug your averaged abdomen measurement and current weight into the calculator and it returns an estimated percentage. The tool then compares that figure to the maximum allowed for your age group, giving you a clear pass or work-needed signal rather than just a raw number.

Treat the output as a planning tool. Trends matter more than any one reading: track your estimate every couple of weeks as you train, and you will see how abdominal measurement responds to changes in diet and conditioning. When an official assessment is on the calendar, measure under the same conditions each time so your home estimates stay comparable, and remember that your unit's graded result is the one that counts on the record.

  • Average three abdomen readings to the nearest half inch, just as a grader would, instead of trusting a single measurement.
  • Measure at the navel at the end of a relaxed exhale, and never suck in or push your stomach out.
  • Compare your weight to the height and weight screening table first; if you are under it, the tape test may not apply at all.
  • Re-check your estimate at the same time of day and in similar conditions so progress between sessions is genuinely comparable.

Read the full guide →

Tool by the Super Simple Digital Tools Team. Reviewed by our editorial team. Free to use, no signup required.

Related tools