Landfill Methane Estimate Calculator
Organic waste buried in landfill decomposes without oxygen and releases methane, a potent greenhouse gas. The IPCC default method estimates the methane generation potential from the waste mass, its degradable organic carbon, the fraction that decomposes, a site correction factor and the methane share of the gas. This calculator multiplies those terms with the carbon-to-methane mass factor of 16 over 12, then converts the result to CO2 equivalent using a global warming potential you enter. Every parameter is a user-editable input so you can match the official defaults for your waste type and site.
Landfill methane formula
CH4 = mass * DOC * DOCf * MCF * F * (16 / 12)
CO2e = CH4 * methane GWP
CH4 per tonne (kg) = CH4 (tonnes) / mass * 1,000
CO2e (kg) = CO2e (tonnes) * 1,000
The factor 16/12 converts the mass of degradable carbon to the mass of methane, since methane (CH4, molar mass 16) carries one carbon atom (molar mass 12). This is the IPCC default-method potential, not a year-by-year emission profile.
Reading the estimate
- DOC and DOCf depend on the waste type: food and garden waste decompose more than inert materials.
- MCF is 1.0 for a managed anaerobic site and lower for shallow or aerobic disposal.
- F is commonly 0.5, meaning landfill gas is roughly half methane and half CO2.
- Gas capture systems collect a share of this methane; subtract your capture efficiency separately.
Landfill methane: frequently asked questions
How is landfill methane estimated?
The IPCC default method estimates the methane potential of waste from its degradable organic carbon (DOC), the fraction that actually decomposes (DOCf), a methane correction factor (MCF) for the site type, and the fraction of landfill gas that is methane (F). The product, scaled by a stoichiometric factor of 16/12 for the carbon-to-methane mass conversion, gives the methane generation potential. All parameters here are editable so you can match official guidance.
What is degradable organic carbon (DOC)?
DOC is the mass of organic carbon in the waste that is available to decompose, expressed as a fraction of wet waste mass. Food, garden, paper and wood wastes have different DOC values. The IPCC and US EPA publish default values by waste type; enter the one matching your waste stream.
Why convert methane to CO2 equivalent?
Methane is a far more potent greenhouse gas than CO2 over a given time horizon. Multiplying methane mass by its global warming potential (GWP) expresses it as the equivalent mass of CO2. The GWP value depends on the time horizon and IPCC assessment report, so it is a user-editable input here.
Is this a regulatory estimate?
No. This is a simplified first-order screening estimate of methane generation potential. Regulatory landfill gas inventories use time-dependent first-order decay models with site-specific data. Use this for rough comparison and education, and consult the official model and your regulator for compliance figures.
Official sources
- IPCC: 2006 IPCC Guidelines, Volume 5: Waste.
- U.S. Environmental Protection Agency: Landfill Methane Outreach Program.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.