Flight CO2 Calculator
Flight CO2 kg from miles, haul band, and cabin.
What it does
Flights emit by the mile with cabin multipliers on top. A 2,500-mile round trip in economy at 0.18 kg per passenger-mile makes 900 kg of CO2, while the same seats up front double or triple the share. Miles, haul band, and cabin set the total.
The tool above runs EPA factors with ICAO multipliers. Enter one-way miles with trip legs, pick the haul band and cabin, and it prints total kg, per-leg kg, and the applied factor. Defaults show the cross-country economy trip; medium-haul practice runs 258 kg economy and 516 business.
Emission bodies supply the constants. EPA Hub tables list short 0.207, medium 0.129-0.131, and long 0.161-0.163 kg per passenger-mile, while ICAO methods fix 3.16 tonnes CO2 per tonne of fuel with economy-to-premium ratios near 1:2 and four-class factors today. Short hops run highest per mile from takeoff shares.
Cabins change footprints without changing fuel much. Premium seats claim more floor area per passenger, so business doubles and first triples the economy share of the same burn. Radiative forcing at altitude adds warming beyond CO2 that this page excludes.
How to use
- Enter one-way miles.
- Enter trip legs (2 = round trip).
- Pick the haul factor band.
- Pick the cabin class.
- Read total kg first, then per leg.
- Compare cabins before booking.
Formula
- miles
- One-way flight miles, 0 to 30,000.
- trips
- Flight legs counted, 1 and up.
- factor
- EPA kg per passenger-mile by haul.
EPA Hub haul factors (2021/2023) with ICAO cabin multipliers (1/1.5/2/3) and the 3.16 fuel constant.
Worked example
Example: cross-country round trip
Defaults: 2,500 miles x2, simple factor, economy.
- Inputs: 2,500 miles, 2 trips, simple 0.18, economy.
- Passenger miles: 2,500 x 2 = 5,000.
- CO2: 5,000 x 0.18 = 900 kg.
- Per leg: 900 / 2 = 450 kg.
- Tool shows 900 kg CO2, 450 kg/leg, 0.18 kg/mile.
Reference table
| Haul | Economy | Business 2x |
|---|---|---|
| Short <300 mi | 0.207 | 0.414 |
| Medium 300-2300 | 0.129 | 0.258 |
| Long 2300+ | 0.163 | 0.326 |
| Simple default | 0.180 | 0.360 |
Limits
- CO2 only. Contrails and forcing excluded.
- Planning factors; loads and aircraft vary.
- Cabin multipliers approximate floor shares.
- Offsets quality unmanaged here.
Common mistakes
- Counting one-way as round trip.
- Economy factors for business seats.
- Ignoring haul bands across trip types.
- Treating offsets as erasers.
- Comparing CO2 without forcing context.
Try it yourself
Quick checks. Answers sit tucked under each question.
1,000 miles x2, medium haul?
2,000 passenger-miles x 0.129 = 258 kg economy. Business x2 = 516 kg.
300 miles x2, short haul economy?
600 x 0.207 = 124.2 kg economy.
Questions
How is flight CO2 figured?
Miles times trips times factor times cabin multiplier. Here 5,000 x 0.18 = 900 kg.
What factors per haul?
EPA 2023: short 0.207, medium 0.129, long 0.163 kg per passenger-mile; simple default 0.18.
How do cabins multiply?
Economy 1x, premium ~1.5x, business 2x, first 3x per ICAO methods.
Does altitude multiply warming?
Radiative forcing at altitude roughly doubles warming vs CO2 alone; this page counts CO2 only.
What is the fuel constant?
Three-point-one-six tonnes CO2 per tonne of jet fuel burned, the ICAO constant.
Are short flights dirtier per mile?
Yes. Takeoffs dominate short hops, which is why short-haul factors run highest.