Skip to main content

Free calculator

Use this calculator to

  • Cost a single appliance per hour, day, week, month and year from its plate rating
  • Compare the annual running cost of two appliances before you buy the replacement
  • Rank equipment by daily kWh to find what is worth putting on a timer or smart plug
  • Build a per-appliance breakdown of a site's annual electricity use

Appliance Running Cost Calculator

Find out how much any appliance costs to run per hour, day, week, and year.

W
hr/day
p/kWh
Running Costs

Formulas

  • Energy/hr = Power (kW)
  • Energy/day = Power (kW) × hours
  • Cost/day = Energy/day × tariff (£/kWh)
  • Cost/year = Cost/day × 365

Related Calculators

CO₂

Carbon Footprint

CO₂ from electricity use, trees offset, car equivalent

Open calculator
LED

LED vs Halogen Payback

Savings, payback period and CO₂ saved by switching to LED

Open calculator
☀kWp

Solar Panel Sizing

Panels needed, system kWp, annual generation and savings

Open calculator

Common scenarios

Select one to run it in the calculator above.

For business

Why this matters for businesses

Single-appliance running cost looks trivial until you multiply by the number of installations, the hours and the years. A 200 W always-on retail display network across 50 sites runs to roughly 87,000 kWh per year, which at 25 p/kWh is over £21,000 of spend that nobody is targeting in a budget review. Catering, refrigeration and IT are the three estates where this maths bites hardest, and where the small kit hides in plain sight on the bill.

The unit rate is only part of the cost. Non-commodity charges (DUoS, TNUoS, BSUoS, CCL, RO, FiT, supplier margin) typically make up around half of a business energy bill, so the true running cost of any always-on appliance is materially higher than the headline p/kWh suggests. For refrigeration in particular, where load runs 24/7 and degrades quietly with seal wear and compressor age, modelling the all-in cost is the only way to size the replacement business case fairly.

Purely Energy benchmarks running cost against tendered offers from 30+ suppliers, with every component (wholesale, NCC, supplier margin, our margin) shown separately on the same page. If you are presenting a refurbishment case to the board, we will give you the per-site running cost on the contract you actually have, and on the contract you could have under the best available tender, so the saving figure on the slide is defensible against scrutiny from finance and from procurement alike.

Common questions

How do I work out what an appliance costs to run?

Convert the power rating to kilowatts, multiply by the hours it runs, then multiply by your unit rate. The arithmetic is kWh = watts x hours / 1000, then cost = kWh x unit rate (p/kWh). A 2,000 W heater running 3 hours uses 6 kWh a day; multiply that by the pence per kWh on your contract and divide by 100 for pounds. The calculator repeats this for hourly, daily, weekly, monthly and annual periods.

Why is the real cost often lower than the plate rating suggests?

The plate rating is the maximum draw, not the average. Thermostatically controlled equipment such as fridges, freezers, ovens and heaters cycles on and off, so a 200 W fridge freezer might average well under half its rating across a day. For cycling appliances, either use the average figure from the energy label or reduce the hours you enter to reflect the actual on time rather than the plugged-in time.

What is the difference between watts and kilowatt-hours?

Watts measure power, the rate at which an appliance draws energy at an instant. Kilowatt-hours measure energy, which is power sustained over time: kWh = kW x hours. Your electricity bill charges for energy, so a 100 W device left on for 10 hours costs exactly the same as a 1,000 W device used for one hour. Both consume 1 kWh.

Does this calculator include the standing charge?

No. The result covers unit-rate cost only: the kWh the appliance consumes multiplied by your pence per kWh. The standing charge is a fixed daily fee you pay regardless of consumption, so it does not change when you add or remove an appliance. To estimate a full bill, add your standing charge in pence per day multiplied by the number of days, and for business supplies allow for the Climate Change Levy and VAT.

Which appliances usually cost a business the most to run?

Anything that turns electricity into heat or runs continuously. Electric space and water heating, commercial refrigeration that never switches off, catering equipment, compressors and air conditioning tend to dominate. A small load running 24 hours a day often outcosts a large load used briefly: a 400 W fridge running all day uses 9.6 kWh, more than a 8,500 W shower used for 20 minutes. Run each candidate through the calculator and rank them by annual kWh.

Related calculators

The conversions that procurement and engineering use alongside this one.

Appliance Running Cost Calculator | UK £/yr | Purely Energy