Energy Direct Debit Calculator: Is Yours Too High?
Have your latest statement handy and we’ll look at the payment together. We’ll account for your estimated annual cost, account balance, 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.
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
Monthly payments are not the same as what you use
Your bill charges for the energy you actually use plus standing charges, and most households use far more in winter than in summer. A direct debit usually spreads the expected yearly cost into equal monthly payments. So in spring and summer you normally pay more than you use and build up credit, and in winter that credit runs down, or the account can move into debit.
That means a credit balance on its own does not show you are overpaying, and a debit balance does not show you are underpaying. What matters is whether twelve months of payments roughly match your estimated yearly cost, after allowing for any balance you are repaying. When your supplier takes the payment, and when your statement is produced, also changes the balance you see on any given day.
Worked example with illustrative figures
Illustrative figures: round numbers chosen to show the method, not current prices. Use the rates on your own bill. The household uses 2,900 kWh of electricity and 10,000 kWh of gas, with the same rates as the energy bill calculator's example.
| Step | Workings | Result |
|---|---|---|
| Estimated annual energy cost | Electricity + gas, usage plus 365 days of standing charges | £1,667.00 |
| Average monthly cost | £1,667.00 ÷ 12 | £138.92 |
| Twelve months of payments | £175.00 × 12 | £2,100.00 |
| Account level (no balance) | £2,100.00 − £1,667.00 = £433.00, 26.0% of the estimate | More than 10% above: the payment may be higher than expected |
| Same payment, £300 debit balance | £2,100.00 − (£1,667.00 + £300.00) = £133.00, 8.0% of the estimate | Within 10%: broadly in line, because part of the payment is clearing the debt |
Worked to full precision and rounded to the nearest penny only at the end. The calculator treats payments within 10% either side of the estimate as broadly in line. That band is a screening rule, not a rule your supplier has to follow.
What to do with the result, and what it cannot tell you
To build the yearly cost from your bill first, use the energy bill calculator. To see how suppliers set the figure, read how energy suppliers calculate monthly payments. If you are repaying arrears, the energy debt repayment calculator helps you plan an affordable amount.
- Give an actual meter reading first. Estimated readings make the yearly cost, and so the result, less reliable.
- If the payment looks high, ask your supplier in writing which kWh figure, rates and balance it used. You can ask for a review or for some credit back, but the outcome depends on your account and the supplier's assessment.
- If the payment looks low, plan for a possible increase rather than a surprise, especially before winter.
- The check does not know your supplier's own forecast, future price changes, discounts, payment plans for arrears or support payments. There is no single right amount of credit for every home.
Related guidance
The PowerGuardian Home Energy Record
A free printable workbook for logging monthly meter readings, bills, Direct Debit payments and account balances in one place — so you can check bills against real readings and evidence a billing dispute if one arises.
PDF workbook · PowerGuardian · free, no email required