Keep Above
What it costs to run
Two appliances that can do the same job rarely draw the same power. This calculator takes each one's rated watts and how long a session runs, a shared number of uses a week, and your own electricity price per kWh — and lands both on a cost per use, per week and per year. Every figure is yours, including the power price; no winner is ever declared.
On the rating plate or label
On the rating plate or label
Put in your price per kWh from your power bill, then each side's rated power and how long one use runs. Nothing here is read from your budgets, and nothing is saved.
| Option A | Option B | |
|---|---|---|
| Rated power | — | — |
| Energy one use takes | — | — |
| Cost of one use | — | — |
| Cost a week | — | — |
| Energy a year | — | — |
| Cost a month | — | — |
| Cost a year | — | — |
How do I compare the running cost of two appliances?
The arithmetic only means something when both sides finish the same job. A session here is defined by what comes out of it — the same meal, the same room at the same warmth, the same load dried — not by what the appliance happens to be doing. Where one side would need a second round to get there, those extra minutes belong in its own minutes field.
Rated power is a ceiling on both sides, but not by the same margin. An appliance holding a temperature spends part of every session coasting with its element off, while one that simply runs — a motor, a pump, a fan — sits much nearer its rating. So costing every minute at full rated power overstates the thermostat side by more than the other, and a meter at the socket is what would settle the real figures.
This is one of the tools built into Keep Above
Keep Above is a budgeting app where you enter your bills and income and it works out the balance you need to keep — so you can see what's safe to spend. No bank connection, no ads on your data.
Running costs never arrive as a bill with a date on it; they show up inside the balance — budgeting apps with no bank connection sets out what each one asks you to keep entering.
About this calculator
Does the daily supply charge belong in the price per kWh?
It does not — this page counts units of electricity, and a fixed daily charge is paid whether either appliance runs or not. Folding it into the rate would spread a standing cost across whichever side happens to run longer, which is the one thing that charge does not depend on. The per-unit rate your own bill states is the figure the field is asking for.
Why is the plate figure a ceiling rather than an average?
A rating plate is a design maximum: the most that appliance would draw, set so the wiring and the fuse behind it are sized for the worst case. What it averages over a run depends on what the appliance does once it is up to temperature or up to speed. This page costs every minute at the plate figure, so what it lands on is the upper end of each side rather than a meter reading — and the two sides are not overstated by the same amount unless they are controlled the same way.
Where is the wattage written on an appliance?
On a plate, sticker or moulded panel somewhere the appliance does not get hot — near the plug, inside a door frame, on the back or underneath. It states watts (W) or kilowatts (kW, where 1 kW is 1 000 W), and where both an input and an output figure are given, the input is the one being paid for. The price per kWh comes off your own bill; this page never assumes one for you.
Why is there only one uses-a-week field for both?
Because the field counts jobs, not appliances. A job that gets done four times a week gets done four times whichever way it is done, so one figure covers both columns. What genuinely differs between two ways of doing it is the length of a session, and that is why the minutes sit on each side separately.