Fuel Gas Engineering Calculator

Fuel and operating conditions

Fuel preset

Choose a preset fuel or enter a custom gas composition. Component percentages must total 100% to calculate results.

Excess air

Use the − / + buttons for precise 0.5% adjustments, or drag the slider for a quick change. Range: 0–100% above stoichiometric air demand.

Air reference

Dry air: 20.95 vol% O₂; mean molecular weight 29 kg/kmol for the volume-basis air calculation. The mass-basis ratio uses 23.14 wt% O₂; the remaining 76.86 wt% is treated as N₂ for the flue-gas balance.

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Composition totals are being checked.

Fuel composition

vol %

Edit component percentages directly. The calculator does not silently normalize inputs; the total must be 100% (within tolerance) for results to be considered valid.

Component	Vol %

Fuel properties

Molecular weight

—

kg/kmol

Density @ 0°C, 1 atm

—

kg/Nm³

Specific gravity vs air

—

dimensionless

LHV

—

MJ/Nm³ at 0°C, 1 atm

HHV

—

MJ/Nm³ at 0°C, 1 atm

LHV by mass

—

MJ/kg

HHV by mass

—

MJ/kg

LHV at 60°F

—

MJ/standard m³ at 60°F, 1 atm

HHV at 60°F

—

MJ/standard m³ at 60°F, 1 atm

Stoichiometric air · volume basis

—

Nm³ air / Nm³ fuel

Stoichiometric air · mass basis

—

kg air / kg fuel (dimensionless ratio)

Combustion products

complete combustion model

Dry CO₂

—

vol %

Dry O₂

—

vol %

Wet H₂O

—

vol %

Dry N₂

—

vol %

Wet flue gas

—

Nm³ / Nm³ fuel

Dry flue gas

—

Nm³ / Nm³ fuel

Fuel properties

Combustion products

Flue gas breakdown