Most sudden jumps come from one of nine causes: a catch-up after estimates, a price rise, a fixed deal ending, colder weather, a meter problem, the wrong meter on your account, a direct debit review, debt being added, or a billing error. Here's how to tell which.
Checked 7 October 2026Written by the MyBillChecker team
The nine common causes
Cause
How to spot it
What to do
Catch-up after estimates
Previous readings marked "E", this one actual
Check the catch-up doesn't include energy used over 12 months ago
Price cap rise
Unit rates changed on 1 January, April, July or October
Compare fixed deals
Fixed deal ended
Tariff name changed
Pick a new deal or check the standard rate
Colder weather
Higher use in winter months
Compare with the same months last year
Faulty or slow meter
Use jumps with no change in your habits
Ask your supplier to test the meter
Someone else's meter
Meter serial number on the bill doesn't match yours
Report it straight away
Direct debit review
Payment up, use the same
Ask how it was worked out
Debt added
A "debt repayment" line
Agree an affordable plan
Billing error
Maths doesn't add up
Use our checker and complain in writing
Prices right now
Ofgem raised the price cap by 4% for a typical household from 1 October to 31 December 2026. The average cap is 26.32p per kWh and 54.83p a day for electricity, with no VAT, and 7.97p per kWh and 29.68p a day for gas, including VAT. VAT came off electricity on 1 October 2026 until 31 March 2027. What changed on 1 October.
Frequently asked questions
Can my supplier just raise my direct debit?
They can review it, but it must be fair and based on your use, tariff and balance. If they can't explain it, complain.
My bill doubled overnight. Is that legal?
It can be if earlier bills were estimates, but you can't usually be billed for energy used more than 12 months ago if the supplier was at fault.
