Calculator

What does your gas meter say?

Drop in your gas smart meter download and see when your heating really runs, what nights left on cost you, and whether anything burns gas around the clock.

Verified: 23 October 2026 from your own meter data, Ofgem’s typical consumption and the price cap
How is this calculated?
Your file stays on this device. Your browser reads it and does the sums here. It is never uploaded, and nothing is saved when you close the page.

Drop your gas usage file here

A CSV of half-hourly, hourly or daily gas readings, in cubic metres or kWh

Where do I get my file?

If you have a smart gas meter, your supplier holds your readings and most let you download them as a CSV from the page that shows your usage in their app or online account. Choose gas, half-hourly if you’re offered a choice, and as long a period as you can.

Gas readings often arrive a day or two late, so yesterday may be missing or only partly there. A week or more gives a much better picture than a single day, and a year gives the best.

Independent calculator. We don’t pass your details to installers. We don’t earn commission from the result. We update underlying rates monthly and source everything from authoritative public data. See the full methodology.

Common questions

Is my gas meter file uploaded anywhere?
No. Your browser reads the file and does every calculation on your own device. Nothing is sent to us or anyone else, and nothing is stored when you close the page.
How do I turn cubic metres of gas into kWh?
Multiply by 1.02264 and by the calorific value on your bill, then divide by 3.6. With a typical calorific value of 39.5, one cubic metre is about 11.22 kWh. This page does it for you, and you can enter the calorific value from your own bill.
How much gas does a typical home use?
Ofgem’s typical home uses 9,500 kWh of gas a year, and a high-use home 14,000 kWh. Most of it is heating, so a home uses several times as much in January as in July. Bigger households and bigger or draughtier houses use more.
Is it cheaper to leave the heating on low all the time?
No. A house loses heat faster the warmer it is inside, so every hour it is held warm when nobody needs it costs gas. Warming it back up uses less than keeping it warm all along. This page shows how much your heating burns from 23:00 to 06:00 and what that adds up to over a year.
What if my gas meter never drops to zero?
Gas used hour after hour with everything off usually means a combi boiler’s keep-hot setting, which fires the boiler every so often, or a pilot light on a gas fire or an older boiler, which burns steadily. The analyser says which your pattern looks like. Switch the heating and hot water off at the boiler for an hour and watch the meter; if it still moves and you can’t find a cause, ask a Gas Safe registered engineer. If you can smell gas, leave the property and call 0800 111 999, or 0800 002 001 in Northern Ireland.