Why Is My Gas Bill So High? Eight Checks to Make

The short answer: check the usage before the payment

If your gas bill is much higher than expected, first compare the meter reading, billing dates and gas used in kWh with the previous statement. Then check the unit rate, standing charge, meter identity and conversion. A larger Direct Debit does not by itself prove that this month’s gas use rose: it may be a payment-plan adjustment intended to cover a debit balance or expected winter costs.

Do not cancel a payment or accuse the meter of being faulty before you have separated those figures. Take a dated photograph of the meter, download the bills you are comparing and write down what you think is wrong. That evidence makes a supplier conversation faster and protects you if the issue becomes a formal complaint.

The checklist below is designed for a domestic gas account. The Ofgem price-cap and Energy Ombudsman details apply to Great Britain; Northern Ireland has separate tariffs and a different consumer-support route.

1. Match the reading and billing period

Find the opening and closing readings on the statement. Look for a marker such as “E” or wording that says a reading is estimated. Citizens Advice says an estimated bill can be too high or too low; if it is high, take a current meter reading and send it to the supplier so the account can be rebilled using actual information.

Check that the closing reading is plausible beside the meter today. Read the whole-number digits from left to right and ignore red digits or digits after the decimal point. If your smart meter is producing estimated statements, it may not be communicating in smart mode. You still need to submit readings until the data problem is fixed; our smart gas meter guide explains the checks.

Also compare like with like. A 92-day autumn statement will naturally be larger than a 30-day summer statement, even at the same daily use. Write down the exact number of days and the kWh used, rather than comparing only the amount due.

2. Separate the Direct Debit from the bill

A Direct Debit is a payment towards the account; the bill records charges for energy and standing charges. The supplier can change a monthly payment after reviewing the account balance and forecast use. That can make the bank payment jump even when the most recent measured consumption has not.

Start with the statement’s opening balance, payments received, energy charges and closing balance. Check that every payment you made appears. If the account is in credit but the payment still rose, ask the supplier for the calculation and the annual-use assumption behind it. If it is in debit, find out whether that debt comes from recent use, old estimates or a missing payment.

3. Check the unit rate and standing-charge days

Compare the gas unit rate in pence per kWh and the daily standing charge with your tariff confirmation. Check whether the statement crosses a price-change date: the supplier may split the period and apply two rates. A fixed tariff should follow its contract, while a standard variable tariff can change with the price-cap period.

For context, Ofgem’s Great Britain average for a capped standard variable tariff paid by Direct Debit from 1 October to 31 December 2026 is 7.97p per kWh plus 29.68p per day. Those figures include 5% VAT on gas. They are averages, not a quote for every region or payment method, and the cap limits rates rather than the total bill. Use the rates printed on your statement when checking your own charge.

Count the standing-charge days once. A 30-day period at 29.68p is £8.90 after rounding. Do not add VAT again to a rate that already includes it. See the current gas price-cap guide for regional and tariff context.

4. Recalculate one billing period

Gas meters record volume, but bills charge for energy in kWh. For a metric meter, subtract the earlier reading from the later one, multiply by the prescribed volume correction factor 1.02264 and the calorific value shown on the bill, then divide by 3.6. An imperial meter needs the extra 2.83 conversion from hundreds of cubic feet to cubic metres.

Suppose a metric meter moves by 80 m³ and the bill shows a calorific value of 39.5. The conversion is 80 × 1.02264 × 39.5 ÷ 3.6 = 897.65 kWh. At 7.97p/kWh, the unrounded usage charge is £71.5428 (£71.54 displayed). Adding the unrounded 30-day standing charge of £8.904 gives £80.4468, or £80.45 to the nearest penny. The tariff figures already include gas VAT, so none is added again.

Keep full precision until the final penny. Use the calorific value and rates on the actual statement, not the illustrative values above. Our gas units to kWh guide shows every conversion step, while the gas bill calculator can check two readings and a billing period.

The total is calculated from unrounded intermediate figures. It excludes any previous balance, payment or account adjustment.

5. Confirm the bill belongs to your meter

In a flat, converted property or meter cupboard, it is possible for records to point to the wrong meter. Compare the meter serial number printed on the bill with the number physically attached to your meter. Citizens Advice also recommends checking the Meter Point Reference Number (MPRN) for the address through the gas-network Find My Supplier service.

If the serial number or MPRN does not match, do not swap labels or test pipework yourself. Photograph the identifying numbers and contact the supplier. If you recently moved, compare the opening photograph with the first bill using our moving-home meter checklist.

6. Look for a real change in gas use

If the readings, rates and arithmetic are right, the higher bill may reflect higher consumption. Compare kWh per day with a similar season, not just the previous month. Colder weather, more hours at home, a higher thermostat setting, hot-water use or a boiler fault can all change consumption.

Measure rather than guess. Take readings at the same time on several days and note heating settings and weather. Never remove a boiler cover, alter a gas valve or interfere with a sealed meter. If you smell gas or suspect a leak in Great Britain, call the National Gas Emergency Service on 0800 111 999; do not treat it as a billing investigation.

7. Check recent meter or supplier changes

A first bill after moving, switching supplier or replacing a meter deserves extra attention. Check that the opening reading agreed by the old and new supplier appears correctly. For a replacement, make sure the closing reading from the removed meter and the opening reading from the new one are both recorded.

A new meter may be metric while an older one was imperial. Citizens Advice warns that a supplier record left in the wrong units can cause overcharging. The physical meter should show m³ for metric or ft³ for imperial. Send photographs and installation paperwork if the bill uses the wrong type.

If a catch-up statement includes consumption from more than 12 months ago, do not assume the whole amount is automatically valid or automatically cancelled. Check the dates and circumstances against the separate gas back-billing rules.

8. Ask for a correction, then use the complaint route

Tell the supplier exactly what you want checked: for example, replace an estimate, correct the meter serial number, explain a tariff change or recalculate a conversion. Attach the meter photograph, bills, tariff confirmation and your arithmetic. Keep the complaint reference and the date it was opened.

Ofgem says suppliers in Great Britain must try to resolve reported problems within eight weeks. You can take the case to the Energy Ombudsman if it remains unresolved after eight weeks or if you receive a deadlock letter sooner. Ofgem does not investigate individual supplier complaints. In England and Wales, Citizens Advice can provide independent support; Scotland uses energyadvice.scot.

Northern Ireland is regulated separately. Complain to the gas supplier first; if the outcome is unsatisfactory or there is no response, the Consumer Council can investigate eligible energy complaints. Do not use Great Britain price-cap rates or the Great Britain escalation route as though they apply unchanged in Northern Ireland.