⚖️Which tariff is actually cheaper for me?

✓ Tested & verified Updated: Aug 9, 2026 How we calculate this

The cheapest unit rate and the cheapest bill are different tariffs more often than not.

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How this works

Put each tariff in its own row with the same yearly usage figure — your own, from a bill — and the tool adds the unit-rate cost to a year of standing charges. The gap between the cheapest and the dearest row is what switching is actually worth, and it is frequently smaller than the difference in headline rates suggests.

What each part of a tariff does

Two tariffs can look alike and cost differently, and it is rarely the headline rate that decides.

Part	Charged	Who it favours
Unit rate	Per kWh used	Everyone, proportionally
Standing charge	Per day, fixed	Heavy users
Off-peak rate	Per kWh in a window	Anyone who can shift load
Exit fee	Once, on leaving early	Nobody

A low unit rate with a high standing charge suits a heavy user; the reverse suits a small flat. Compare on total cost for your own usage, never on rate alone.

Frequently asked questions

Where do I find my yearly usage?

On an annual statement, or by taking two meter readings a year apart. Most suppliers show an estimated annual consumption on the bill. Using your own figure is the entire point — a comparison run on an average household is a comparison of somebody else.

Why does the standing charge matter so much?

Because it is charged whether you use anything or not. At 40 cents a day it is 146 a year before a single kilowatt-hour. For a small flat that can outweigh a better unit rate; for a large all-electric house it rarely does.

What about time-of-use tariffs?

Enter them as two rows — one for the usage you can move into the cheap window and one for the rest — or use your blended average rate if you know it. A single unit rate cannot describe a tariff with three of them.

How we calculate this

Each row is usage × unit rate + (standing charge ÷ 100 × 365), so the standing charge is entered in cents or pence per day and converted. No exit fees, discounts or introductory periods are modelled — those are worth noting in the tariff name, because they change what the comparison means rather than what it calculates.