Convert m³ Natural Gas to kg
The value above comes from a published dataset (DEFRA, EPA, IPCC) that's revised about yearly. Get one email when this number changes: old → new, and what it means. No marketing.
A cubic metre of natural gas weighs 0.808 kg [GreenCalculus fuel_properties.natural_gas.density_kg_m3 · DEFRA 2026 'Fuel properties' tab — Natural gas · v2026.203] — well under a kilogram. That is the fact most people get wrong, and by a wide margin: a cubic metre of anything invites an intuition borrowed from liquids, where the same volume of water weighs a tonne. Gas is roughly 1,200 times lighter than water, and the conversion between the volume a meter reads and the mass the supply chain accounts in turns entirely on that.
To convert cubic metres of natural gas to kilograms, multiply by 0.808. So 1,000 m³ is 808 kg. To go the other way, multiply kilograms by 1.238 — one kilogram of natural gas occupies about 1.24 m³, and a tonne occupies roughly 1,238 m³.
kg = m³ × density, where the reference density of natural gas is 0.808 kg/m³ [GreenCalculus fuel_properties.natural_gas.density_kg_m3]. Reverse: m³ = kg ÷ density. The density is measured and read live from the reference dataset, so the page restates itself when the source does.
| Cubic metres | × 0.808 | Kilograms |
|---|---|---|
| 1 m³ | × 0.808 | 0.808 kg |
| 100 m³ | × 0.808 | 80.8 kg |
| 1,000 m³ | × 0.808 | 808 kg |
| 1,238 m³ | × 0.808 | 1,000 kg — one tonne |
| 1,000,000 m³ | × 0.808 | 808 tonnes |
How to convert m³ of natural gas to kg
Multiply by 0.808. Because the figure is just under one, the kilogram number and the cubic-metre number look deceptively similar — 1,000 m³ is 808 kg — which makes this conversion easy to skip mentally and get roughly right. The place it goes wrong is at the tonne boundary: a tonne of natural gas is about 1,238 m³, not a thousand.
Kilograms to m³ of natural gas
Multiply by 1.238. So 500 kg is 619 m³, and 10 tonnes is 12,376 m³. This is the direction needed when a mass-based figure — an LNG cargo, a methane leakage estimate, a per-tonne emission factor — has to be reconciled against metered volume.
Why a cubic metre of gas is not simply a cubic metre
This is the caveat that distinguishes a gas conversion from a liquid one, and it is worth stating plainly.
A litre of diesel is a litre. A cubic metre of gas is a volume of something compressible, and its mass depends on the pressure and temperature it is held at, and on what is actually in it. Pipeline gas is mostly methane, but the fraction varies by field and by network, and inert content shifts the density further. The figure here is a reference density for a reference composition — the right basis for reporting, reconciliation and factor application, and the wrong basis for a specific meter under specific conditions. If you are working from a pressurised or non-standard measurement, correct it to standard conditions first.
This is also why gas is billed by energy rather than by volume in many markets: the UK converts metered cubic metres to kilowatt-hours using a calorific value that varies with the gas actually delivered, precisely because a cubic metre is not a stable quantity of anything. The calorific value entry covers that side.
Where this conversion is needed
- Methane leakage and venting — leak rates and fugitive emissions are quantified in mass, but detection and metering often produce volume. Getting between the two is the first step in any methane quantification.
- LNG and bulk gas logistics — cargoes are traded in tonnes while pipelines and regasification are volumetric.
- Per-tonne emission factors — where a factor is published per tonne of gas rather than per cubic metre.
- Upstream and production accounting — field output is reported by mass; distribution is metered by volume.
For the liquid-fuel equivalent of this page, litres of diesel to kg. For diesel as energy rather than mass, litres of diesel to kWh. For the energy units gas is billed in, kWh to GJ and kWh to therms.
Natural gas produces emissions two quite different ways — burned, it is stationary combustion producing mostly CO₂; released unburned, it is methane, with a far higher warming effect over any horizon. Converting volume to mass is a step towards either, not a substitute for either. For combustion use the stationary combustion calculator and the natural gas combustion methodology; for fugitive releases, the oil and gas methane calculator.
Frequently Asked Questions
About 0.808 kg — well under a kilogram. This surprises most people, because a cubic metre invites an intuition borrowed from liquids: the same volume of water weighs a tonne. Natural gas is roughly 1,200 times lighter than water.
About 1,238 m³. This is the place the conversion most often goes wrong: because 0.808 is close to one, 1,000 m³ and 808 kg look similar enough that people assume a tonne is about a thousand cubic metres. It is nearer 1,240.
Multiply cubic metres by 0.808. To reverse it, multiply kilograms by 1.238. Both figures assume a reference composition at standard conditions.
Considerably more than a liquid’s does. Gas is compressible, so its mass per cubic metre depends on pressure and temperature, and its composition varies by field and by network — the methane fraction and the inert content both shift the density. The figure used here is a reference density for a reference composition, which is the right basis for reporting and factor application but not for a specific meter under non-standard conditions.
Because a cubic metre is not a stable quantity of anything. The energy a given volume delivers depends on its composition, so many markets meter volume and then convert to energy using the calorific value of the gas actually supplied. Billing on energy means customers pay for what they receive rather than for a volume of variable content.
Close but not identical. Natural gas is predominantly methane with other hydrocarbons and inert gases mixed in, and those change the density slightly. For leakage and fugitive-emissions work the distinction matters, because the warming effect is attributed to the methane fraction specifically rather than to the whole stream.
Because the supply chain accounts in mass above the meter. LNG cargoes are traded in tonnes, field production is reported by mass, methane leak rates are quantified in kilograms, and some emission factors are published per tonne of fuel. Volume is what the meter reads; mass is what most of the paperwork above it uses.
No — and the answer depends sharply on what happens to the gas. Burned, it produces mostly carbon dioxide. Released unburned, it is methane, with a far greater warming effect over any time horizon. This conversion is a step towards either calculation, not a substitute for one.