Food Miles vs Flight Emissions Calculator
The food miles and flight emissions calculators are the two transport-emissions scenario tools on this site, and each page links to the other as the related tool for other modes. Both estimate greenhouse-gas scenarios from distance, a user-entered emissions factor, and a quantity that scales the factor. The difference is the quantity being moved and the structure around it. The food miles calculator estimates emissions from shipping goods over one freight leg: tonne-kilometres equal shipment mass in kilograms divided by 1,000 times distance in kilometres, and transport emissions equal tonne-kilometres times the factor in kg CO₂e per tonne-kilometre. The flight emissions calculator estimates a base flight CO₂ scenario from passenger distance, cabin class, and an entered emissions factor, with an optional non-CO₂ radiative-forcing multiplier applied on top.
Neither calculator supplies the factor, and both are educational worksheets for directional scenario comparisons rather than inventories, certifications, offsets, or compliance filings.
What each calculator does
The food miles calculator takes shipment mass in kilograms, distance in kilometres, and a nonnegative factor in kg CO₂e per tonne-kilometre. It reports transport work in tonne-kilometres and a transport-only emissions scenario in kg CO₂e, both displayed to one decimal place, using the entered values without intermediate rounding. The factor is not supplied: you record its transport mode, geography, year, system boundary, source, version, and an uncertainty or sensitivity range. For a multi-mode journey, the page recommends one run per leg rather than one factor for the whole distance.
The flight emissions calculator takes passenger distance, cabin class, an entered emissions factor, and an optional radiative-forcing multiplier. Base CO₂ equals passenger distance times the entered factor times the cabin multiplier; the optional scenario equals base CO₂ times the entered radiative-forcing multiplier. The worked example on the page uses 1,000 passenger-kilometres at 0.12 kg CO₂ per passenger-kilometre with a cabin multiplier of 1, giving 120 kg base CO₂; a radiative-forcing multiplier of 1.7 turns that into 204 kg CO₂e, while 0 leaves the optional scenario at zero without changing the base. The page reports no car or tree equivalents and requires the factor’s source, cabin treatment, geography, and year.
Side-by-side comparison
| Feature | Food miles calculator | Flight emissions calculator |
|---|---|---|
| Quantity moved | Goods over one freight leg | Passengers on a flight |
| Inputs | Shipment mass (kg), distance (km), entered kg CO₂e per tonne-km factor | Passenger distance, cabin class, entered factor, optional radiative-forcing multiplier |
| Core relationship | t-km = mass ÷ 1,000 × distance; emissions = t-km × factor | Base CO₂ = distance × factor × cabin multiplier; optional = base × RF multiplier |
| Worked example | 500 kg over 1,000 km at 0.062 kg CO₂e/t-km gives 31.0 kg CO₂e and 500.0 t-km | 1,000 passenger-km at 0.12 kg CO₂/passenger-km, cabin multiplier 1, gives 120 kg; RF 1.7 gives 204 kg CO₂e |
| Factor provenance | Mode, geography, year, system boundary, source, version, uncertainty | Factor version, geography, year, cabin treatment, RF choice |
| What it is not | Not a product footprint, inventory, certification, or offset; one leg only | Not an exact footprint; no car or tree equivalents |
| Best for | Freight leg audits and one-change-at-a-time scenario comparisons | Flight scenario comparisons with an optional non-CO₂ view |
When to use which
Use the food miles calculator when your question is about shipping goods — for example, comparing transport modes or distances for a food shipment, or auditing a journey leg by leg. It is the right tool when you can weigh the shipment and measure the route, because the tonne-kilometre structure keeps mass, distance, and factor effects separate. Use the flight emissions calculator when your question is about passenger air travel, especially if you want to see the effect of cabin class or of including the optional radiative-forcing multiplier.
The two can be used together for a multi-modal journey that includes both freight and air legs, but keep the boundaries separate: the food miles result is transport-only emissions for the leg you enter, and the flight result is a base CO₂ scenario with an optional RF view. Both pages treat low-and-high factor reruns as sensitivity ranges, not confidence intervals, and neither result establishes code compliance, certification, safety, forecast accuracy, or model validity. For lifecycle emissions of the food itself, the food miles page points to the meat footprint calculator, and for household energy scenarios the flight emissions page points to the home energy efficiency calculator.
Where to start
- Food miles calculator — transport-only freight emissions from mass, distance, and an entered tonne-kilometre factor.
- Flight emissions calculator — passenger flight CO₂ from distance, cabin class, and an entered factor, with an optional radiative-forcing scenario.
Informational note: This page is an educational comparison of two scenario calculators, not an inventory, certification, offset, or compliance tool. Every empirical factor is a value you supply, so results are only as meaningful as the documented provenance behind the inputs. Align definitions, system boundaries, and factor versions before comparing any result with published statistics.