Free tool
Natural gas unit converter
Volumes convert exactly. Energy and CO2e do not, because both need a factor that varies with your gas or your reporting rule. Those factors are editable here, and every one of them is named with its source.
Factors last reviewed
The factors, and where each comes from
| Factor | Value | Source | In force |
|---|---|---|---|
| Methane to CO2e | 28 | 40 CFR 98 Table A-1 | Since 1 Jan 2025, was 25 |
| Nitrous oxide to CO2e | 265 | 40 CFR 98 Table A-1 | Since 1 Jan 2025, was 298 |
| Heating value | 1037 Btu/scf | EIA US average, 2025 | Varies by gas; editable above |
| Mcf to scf | 1,000 | Definition | Exact |
IPCC AR6 values, which no US reporting rule requires today, are listed separately below.
Volume and energy
Volume to volume is fixed arithmetic. Volume to energy is not: it depends on how much heat your gas actually carries, so the heating value is a field you can edit.
BOE uses the SEC and industry convention of 6 Mcf to one barrel. That is an energy equivalence at the burner tip and says nothing about relative value at the wellhead, where the ratio is rarely 6:1.
The 1037 Btu/scf default is EIA's 2025 US average. EIA notes that heat content shifts with location, with the type of customer, and over time. If you have a gas analysis, type its number in instead.
- scf
- 1,000
- Mcf
- 1
- MMcf
- 0.001
- Bcf
- 0.000001
- MMBtu
- 1.037
- therm
- 10.37
- GJ
- 1.0941
- BOE
- 0.166667
- Sm3
- 28.2623
- Nm3
- 26.7911
Methane and nitrous oxide to CO2e
Mass times global warming potential. The potential you use depends on what you are filing under, and the two US answers differ by 12 percent, so pick the one that applies to you.
Effective 1 January 2025. What the EPA Greenhouse Gas Reporting Program requires today.
One standard atmosphere. The scientific and API base.
The list holds the two values US rules actually require. IPCC AR6 gives 29.8 for fossil methane, 27.0 for non-fossil, and 273 for nitrous oxide (IPCC AR6 Working Group I, Table 7.15). Fossil is the one covering oil and gas leaks. Why it is not in this list.
- Gas mass
- 1
- tonnes
- CO2e
- 28
- tonnes CO2e
- CO2e
- 28,000
- kg CO2e
- Multiplier used
- 28
- GWP, 100-year
Volume inputs assume pure gas at 60 °F and the pressure base you picked, against a molar mass of 16.043 for methane. The base matters: Texas reports at 14.65 psia, so running RRC volumes through the 14.696 default overstates mass, and CO 2e with it, by about 0.31 percent. Real pipeline gas is also a mixture, so a measured mass will beat this for anything you have to defend.
Emission rate
A leak survey reports grams or kilograms an hour. A permit is written in tonnes a year. An engineer thinks in scfh. Same leak, three vocabularies.
Annualised at 8,760 hours, and volume rates cross to mass through the same standard-condition density the CO2e panel uses, so a leak quoted in scfh and the same leak in kg/hr cannot disagree.
- kg/hr
- 1
- g/hr
- 1,000
- kg/day
- 24
- t/yr
- 8.76
- scfh
- 52.148
- Mcf/d
- 1.2516
Mcf to MMBtu
An Mcf is a thousand cubic feet of gas, a volume. An MMBtu is a million British thermal units, an amount of energy. Converting one to the other needs the heat content of the gas:
MMBtu = Mcf × 1,000 × (Btu per cubic foot) ÷ 1,000,000
At the US average of 1037 Btu per cubic foot, one Mcf is 1.037 MMBtu, and one MMBtu is 0.9643 Mcf. Both figures shift with the gas itself. The EIA publishes 1037 Btu per cubic foot as the 2025 average delivered to end-use sectors, and states plainly that heat content varies by location, by consumer type and over time. If you have a gas analysis, use its number in the field above.
Mcf to MMBtu chart
At 1037 Btu per cubic foot. Change the heating value above and the calculator moves; this chart is fixed at the US average.
| Mcf | MMBtu | therms | scf |
|---|---|---|---|
| 0.1 | 0.1037 | 1.037 | 100 |
| 0.5 | 0.5185 | 5.185 | 500 |
| 1 | 1.037 | 10.37 | 1,000 |
| 2 | 2.074 | 20.74 | 2,000 |
| 5 | 5.185 | 51.85 | 5,000 |
| 10 | 10.37 | 103.7 | 10,000 |
| 25 | 25.925 | 259.25 | 25,000 |
| 50 | 51.85 | 518.5 | 50,000 |
| 100 | 103.7 | 1,037 | 100,000 |
| 250 | 259.25 | 2,593 | 250,000 |
| 500 | 518.5 | 5,185 | 500,000 |
| 1,000 | 1,037 | 10,370 | 1,000,000 |
| 2,500 | 2,593 | 25,925 | 2,500,000 |
| 5,000 | 5,185 | 51,850 | 5,000,000 |
| 10,000 | 10,370 | 103,700 | 10,000,000 |
The MMBtu and therm columns depend on the heating value. The scf column does not.
scf to Mcf, and the MMcf and Bcf trap
These are all volumes, and the conversions between them are exact definitions with no factor to argue about. The prefixes trip people up because they are Roman numerals, not metric ones: the M in Mcf is a thousand, so MMcf is a thousand thousand.
| Unit | scf | Mcf | MMcf | Bcf |
|---|---|---|---|---|
| 1 scf | 1 | 0.001 | 0.000001 | 1.0000e-9 |
| 1 Mcf | 1,000 | 1 | 0.001 | 0.000001 |
| 1 MMcf | 1,000,000 | 1,000 | 1 | 0.001 |
| 1 Bcf | 1,000,000,000 | 1,000,000 | 1,000 | 1 |
State agencies report production in these units, and which one they choose differs by state. Our per-state data pages give the volumes each agency publishes, and the API well number decoder will tell you which agency a given well answers to.
What CO2e means, and why the multiplier is contested
CO2e restates a quantity of any greenhouse gas as the amount of carbon dioxide that would cause the same warming over a chosen period. The arithmetic is trivial:
CO2e = mass of gas × global warming potential
The argument is over the multiplier. For methane, 40 CFR 98 Table A-1 currently specifies 28 over 100 years, so a tonne of methane is 28 tonnes CO2e. That row of the table was changed by the final rule published on 25 April 2024, effective 1 January 2025. Before that, the same table said 25, and a tonne of methane was 25 tonnes CO2e.
That is 12 percent on every methane figure you report. A fair amount of published guidance has not caught up, including pages still sitting on federal websites, which is why the basis is a field you set rather than a default we apply on your behalf. If you file under Subpart W, we walk through what is still required in GHGRP Subpart W reporting in 2026.
What about the IPCC AR6 values?
The Sixth Assessment Report is the current science, and it is where the range EPA describes as 27 to 30 comes from. AR6 splits methane by the origin of its carbon, which is the detail that range hides:
- Fossil methane, GWP-100 29.8
- Methane from oil and gas systems and coal. When it oxidises it adds carbon dioxide that was not previously in the atmosphere, so it carries the higher figure. This is the AR6 value that applies to oil and gas fugitive emissions.
- Non-fossil methane, GWP-100 27.0
- Biogenic sources, where oxidation returns carbon that was recently in the atmosphere.
- Nitrous oxide, GWP-100 273
- Against 265 in the current Table A-1.
Source: IPCC AR6 Working Group I, Table 7.15. These are not offered in the calculator above, and that is deliberate. No US reporting rule requires them today, and putting a research value in the same dropdown as the regulatory ones is how the wrong number reaches a filing. Use them when a voluntary framework asks for AR6, such as a corporate inventory or an OGMP 2.0 submission that specifies it; use Table A-1 for anything filed under 40 CFR 98.
In practice that means an operator reporting fossil methane on an AR6 basis uses 29.8, sitting 6 percent above the 28 in Table A-1 today and 19 percent above the 25 that applied before 2025. All three are defensible. Which one you used is the thing worth writing down. State programmes add their own wrinkles: Colorado's intensity rule has a verification factor on top, and its annual inventory has its own June 30 deadline.
Methane to CO2e, by volume
Converting a volume of methane to CO2e adds a step, because global warming potential applies to mass. At standard conditions of 60 °F and 14.696 psia, one Mcf of pure methane weighs 19.18 kg, which at a GWP of 28 is 537 kg CO2e.
Treat it as an upper bound for pipeline gas. Produced gas is a mixture, and the methane fraction moves around by basin and by well, so a measured composition will always beat this assumption where the number has to hold up.
Methane to CO2e chart
The same tonnage under both US bases, so the size of the change is visible rather than asserted.
| Tonnes CH4 | t CO2e, Table A-1 (28) | t CO2e, AR4 (25) |
|---|---|---|
| 0.1 | 2.8 | 2.5 |
| 0.5 | 14 | 12.5 |
| 1 | 28 | 25 |
| 5 | 140 | 125 |
| 10 | 280 | 250 |
| 25 | 700 | 625 |
| 50 | 1,400 | 1,250 |
| 100 | 2,800 | 2,500 |
| 500 | 14,000 | 12,500 |
| 1,000 | 28,000 | 25,000 |
Where these factors come from
- Volume conversions
- Definitions of the units. Exact, no source needed.
- Heating value, 1037 Btu/scf
- US Energy Information Administration, average heat content of natural gas delivered to end-use sectors, 2025. Adjustable above because EIA states it varies.
- 40 CFR 98 Table A-1 (current)
- CH4 28, N2O 265.
- IPCC AR4 (pre-2025 GHGRP)
- CH4 25, N2O 298.
- IPCC AR6 (reference only, not selectable)
- CH4 29.8 fossil, 27.0 non-fossil, N2O 273. IPCC AR6 Working Group I, Table 7.15. Current science, but not required by any US reporting rule today. Why it is not in the dropdown.
- Standard conditions
- 60 °F and 14.696 psia, giving 379.48 scf per lb-mol. Used only for the volume-to-mass step.
Working with real production data?
TetraSoft Atlas maps wells, production and emissions across eight states, with the volumes each agency reported already loaded. Free to explore.
Open the Atlas dashboard →Frequently asked questions
How many MMBtu are in an Mcf of natural gas?
About 1.037 MMBtu, using the US average heating value of 1037 Btu per cubic foot. The figure is not fixed: an Mcf is a volume and an MMBtu is an amount of energy, so the conversion depends on the heat content of your particular gas. Richer gas carries more Btu per cubic foot and converts to more MMBtu.
How many scf are in an Mcf?
Exactly 1,000. The M in Mcf is the Roman numeral for a thousand, not the metric mega. It catches people out on MMcf, which works out to a million cubic feet because it is a thousand thousand.
What is the difference between Mcf and MMBtu?
Mcf measures volume and MMBtu measures energy. Two Mcf of gas from different fields hold the same volume but not the same energy, which is why gas is bought and sold on heat content while production is reported by volume. Converting between them always requires a heating value.
What is CO2e?
CO2e, or carbon dioxide equivalent, expresses a quantity of any greenhouse gas as the amount of CO2 that would cause the same warming over a chosen period. It is the mass of the gas multiplied by its global warming potential, almost always over 100 years.
How do you convert methane to CO2e?
Multiply the mass of methane by its global warming potential. Under 40 CFR 98 Table A-1 that multiplier is 28, so one tonne of methane is 28 tonnes CO2e. The methane row of that table was updated by the final rule published on 25 April 2024, effective 1 January 2025; before that the multiplier was 25.
Is the global warming potential of methane 25 or 28?
Both, depending on the programme. The EPA Greenhouse Gas Reporting Program requires 28 today, but required 25 before 1 January 2025, and some state programmes still cite the older value. The IPCC Sixth Assessment Report gives a third answer again: GWP-100 of 29.8 for fossil methane, which is the figure that applies to oil and gas fugitive emissions, and 27.0 for non-fossil methane. AR6 is not required by any US rule today, so this calculator lists only the two US regulatory values and asks you which one applies.