How does this calculator decide whether a payment is reasonable?

It estimates your annual energy cost from your own kWh usage, unit rates and standing charges, compares that with twelve months of your direct debit, then adjusts for any debit balance you are repaying, the time of year and whether your readings are actual or estimated. It never judges a payment from the account balance alone.

Is the result a bill or a guarantee?

No. It is an estimate based on the figures you enter. It is not a supplier bill, not financial advice, and not a guarantee that your payment should change.

Where do I find the figures it asks for?

Your latest energy statement shows your unit rates in pence per kWh, standing charges in pence per day, your annual consumption in kWh and your account balance. Your bank statement or supplier account shows the monthly direct debit.

What if my readings are estimated?

Submit an actual reading first. The calculator flags estimated readings and will hold back a confident verdict where the result is borderline, because the underlying consumption figure cannot be relied on.

Is it worth switching energy supplier right now?

It depends on your current tariff versus the best available deals. Use our comparison and 'should I switch?' tools to see whether a fixed or better variable deal would save you money today.

How long does switching energy supplier take?

A switch typically completes within five working days, and there's a 14-day cooling-off period. Your supply is never interrupted — the same gas and electricity flow into your home.

Are there exit fees for switching?

Some fixed tariffs charge exit fees of around £30–£60 per fuel if you leave early. Variable and rolling tariffs usually have none. Always check before switching.

Will switching supplier interrupt my supply?

No. Switching only changes who bills you; the physical gas and electricity supply continues uninterrupted with no work needed at your home.

Should I choose a fixed or variable tariff?

Fixed tariffs lock your unit rates and protect against rises; variable tariffs follow the market and can fall. If prices are expected to drop, variable can win, but it carries more risk.

Energy Direct Debit Reasonableness Calculator

Enter the figures from your latest energy statement. This tool compares twelve months of your direct debit against your estimated annual energy cost, then takes account of your balance, the time of year and whether your readings are actual or estimated.

Pre-filled from your saved My PowerGuardian details: annual electricity use, annual gas use. Every value can be changed below.

Your energy details

Annual electricity use (kWh)

Electricity unit rate (p/kWh)

Electricity standing charge (p/day)

Does your home use mains gas?

Annual gas use (kWh)

Gas unit rate (p/kWh)

Gas standing charge (p/day)

Your payments and balance

Current monthly direct debit (£)

Current account balance (£)

Is that balance credit or debt?

Month you are checking

Are your meter readings actual or estimated?

Tariff or price change in the last three months?

How the calculation works

Annual electricity cost = annual electricity kWh × unit rate + 365 × standing charge
Annual gas cost = annual gas kWh × unit rate + 365 × standing charge
Pence figures are divided by 100 to give pounds
Average monthly cost = estimated annual cost ÷ 12
Annual payments = current monthly direct debit × 12
A debit balance is added to the expected annual collection before the payment is judged, so repaying arrears is not mistaken for overpaying

Related guidance

The Complete UK Guide to Energy Direct DebitsHow payments are set, reviewed and challenged.Is my energy direct debit too high?The full check behind this calculator.How much energy credit should I have?Interpret your balance in context.Can I ask for my energy credit back?Requesting a refund, step by step.

Frequently asked questions

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Energy Direct Debit Reasonableness Calculator

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How the calculation works

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