Diet Carbon Footprint Calculator
What you eat has a measurable climate footprint, and food groups differ widely: animal products generally carry far higher emissions per kilogram than plant foods. This calculator estimates the annual carbon footprint of your diet from your weekly servings of meat, dairy and plant foods, the mass of each serving and an emission factor per kilogram. Every emission factor and serving mass is a user-editable input, so you can use figures from an official life-cycle source and compare scenarios such as cutting back on meat.
Diet carbon footprint formula
Group CO2e/week = servings * serving mass * group factor
Weekly CO2e = meat + dairy + plant group totals
Annual CO2e = weekly CO2e * 52
Meat share = meat group CO2e / weekly CO2e * 100
Each group uses the same serving mass for simplicity; adjust it to reflect your typical portions. The meat share highlights where most of your dietary emissions come from.
Lowering your diet's footprint
- Reducing high-factor foods (red meat, hard cheese) cuts the most per serving swapped.
- Plant proteins generally carry a fraction of the footprint of animal proteins.
- Cutting food waste compounds the saving on top of food choices.
- Use life-cycle factors from an official source and note their scope and region.
Diet carbon footprint: frequently asked questions
How is a diet's carbon footprint calculated?
For each food group, multiply your weekly servings by the mass per serving and by an emission factor in kg CO2e per kg of food, then add the groups and scale to a year. This calculator does that for meat, dairy and plant foods, with every emission factor as an editable input so you can use figures from an official life-cycle source.
Why do meat and dairy have higher footprints?
Animal products require feed, land and energy, and ruminant animals such as cattle produce methane during digestion. Life-cycle studies consistently show meat and dairy have higher emissions per kilogram than most plant foods. Enter the specific factors you want to use from your chosen authority.
What serving mass should I use?
Use the average cooked or as-eaten mass of a typical serving for each group. Dietary guidelines from agencies such as the USDA give serving sizes you can adapt. Serving mass is an editable input so you can match your own portions.
Does cutting meat lower my footprint a lot?
For most diets, reducing high-footprint animal products is the single largest lever on food emissions. The calculator lets you change servings to compare scenarios, such as swapping some meat servings for plant foods.
Official sources
- U.S. Environmental Protection Agency: Sustainable Management of Food.
- U.S. Department of Agriculture: Dietary Guidelines for Americans.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.