SmartCost Lab

Home Office Electricity Cost Calculator

List the equipment you use when working from home and see the extra electricity it adds per day, week and year — with room to include a space heater or air conditioning you only run because you're home.

Last reviewed 16 October 2026 · How we build and check calculators

Devices you use for work

Example wattages — check each device's label or power adapter, or measure with a plug-in energy monitor. Typical use is often well below the adapter's maximum rating.

days
weeks

Example: 52 weeks minus holidays and other days away.

kWh

Only if you heat or cool the house more because you're home. For an electric heater: watts × hours ÷ 1,000 (e.g. 1,000 W for 4 hours = 4 kWh). For gas heating, use our Home Heating Cost calculator instead.

¢/kWh

The price per kWh on your bill, including any taxes already built into it.

Reference rate: 18.31 ¢/kWh — U.S. average residential electricity price (average revenue per kWh, so fixed charges are already spread in; monthly, preliminary), U.S. EIA, Electric Power Monthly, Table 5.6.A, July 2026 (preliminary). Enter your own rate from your bill.

Extra electricity per year from working at home

$15.77

$0.11 per home-working day · 86 kWh a year

Per week
$0.34
Per month (average)
$1.31
Home-working days
138

per year

Heating/cooling share
$0.00

per year

Yearly cost by device
Show data table
Laptop$10.11
External monitor$5.05
Desk lamp (LED)$0.61

The equipment usually costs less than you think

Laptops are remarkably frugal: many draw tens of watts while working, far below the maximum printed on their charger. An external monitor, a router you'd run anyway and LED lighting add little. Run the calculator with realistic numbers and the devices themselves often come to a modest sum per working day. The cost that changes everything is keeping the house warm or cool all day — which is why there's a separate field for it.

How the estimate works

device kWh per day = Σ (watts × hours) ÷ 1,000 home-working days = days per week × working weeks per year yearly cost = (device kWh + extra heating/cooling kWh) × days × price per kWh

Each row in the device list is costed separately, so the chart shows which item dominates. Use the scenario tabs to compare, say, three home days a week against five.

Estimating the heating or cooling part

If you switch on an electric heater or an air conditioner only because you're working at home, enter its extra daily energy: watts × hours ÷ 1,000. A 1,000 W heater on for four hours adds 4 kWh a day. If your home is heated by gas, oil or a heat pump, the extra cost depends on that system — work it out with the Home Heating Cost calculator and compare.

Remember the flip side: a day at home is often a day without commuting. The Commute Cost calculator shows what that saves.

Can you claim it on tax?

Tax authorities in all four countries have rules for home-working costs, and they change often — flat-rate methods, eligibility tests for employees versus the self-employed, and record-keeping requirements all differ. We link to the official guidance below rather than quoting rates that may be out of date. This calculator's yearly figure can help if you use an actual-cost method, but check the rules for your situation or ask a tax professional.

Sources

Results are estimates based on the figures you enter and the stated assumptions. They are not financial, tax, legal or engineering advice. Spotted a problem? Tell us.