MundoKit

Appliance Electricity Cost Calculator

Use measured kWh over a representative sample or enter active watts, enabled hours and duty cycle. Add inactive power to estimate energy and cost.

Inputs
W
h
%
W
Includes off-duty portions of enabled hours and the rest of the day.
currency/kWh

Results

Cost for modeled period
8.16 currency units
Energy for modeled period
96 kWh
Average daily energy
0.8 kWh
Daily inactive energy
0 kWh
  • Measured mode scales your sample to the selected days and already includes standby. Choose a representative sample covering cycling and actual settings.
  • Days include all enabled and inactive hours. Use zero inactive power if the appliance is disconnected outside operation. Fixed utility charges are excluded.

Results update as you type. The share link stores your inputs after the # in the address, which is not sent to our server, but anyone you send it to can read them.

How it works

Virginia Tech gives energy as watts × hours ÷ 1000 and cost as kWh × the electricity rate. Duty cycle converts enabled hours into actual active hours; inactive power covers every remaining hour.

Active hours = enabled hours × duty cycle ÷ 100 Daily kWh = [active watts × active hours + inactive watts × (24 − active hours)] ÷ 1000 Measured daily kWh = sample kWh ÷ sample hours × 24 Period cost = daily kWh × days × rate

Measured mode already includes cycling and standby, so no extra standby allowance is added. Scaling assumes the sample is representative. Nameplate power may differ from actual draw. This tool does not use a universal refrigerator duty cycle.

All prefilled prices, loads and performance assumptions are hypothetical examples. Use one currency throughout. Calculations keep full precision internally; displayed energy and money are rounded, and year-end payback is shown in whole years where applicable.

Worked examples

Virginia Tech window-fan example

A 200 W fan used four hours per day, 100% duty cycle and zero standby for 120 days consumes 96 kWh. At the example rate 0.085 per kWh, cost is 8.16.

Measured cycling appliance

A meter records 2 kWh over 48 hours. Average daily consumption is 1 kWh. Over 30 days at 0.30 per kWh, consumption is 30 kWh and cost is 9.00.

Frequently asked questions

Should I use nameplate watts?
Measured energy is better for variable or cycling loads. Nameplate watts and guessed duty cycles are estimates.
What does duty cycle mean?
It is the fraction of enabled hours at active power. Four enabled hours at 50% duty means two active hours.
When does standby apply?
Inactive power applies during all 24 hours outside actual active hours, including off-duty portions of enabled time.
Can I use an energy-label annual kWh figure?
Yes. Enter it as measured energy with sample hours equal to the days covered multiplied by 24, then choose the desired period.
Does it estimate the whole electricity bill?
No. It estimates consumption charges for this appliance. Fixed fees, tiers and demand charges are outside the model.

Sources

Last reviewed 2026-11-14. The method is written out above so you can check our math.