The CO2 breathing emission and meat footprint calculators both turn entered assumptions into a CO2 mass, but they answer different questions. The breathing calculator converts a physiological scenario — breathing rate, tidal volume, exhaled CO2 fraction, and duration — into gas volume and then mass. The meat footprint calculator converts servings into food mass and applies an entered lifecycle factor to estimate CO2-equivalent emissions. One is gas-exchange arithmetic; the other is a food lifecycle scenario.
What each calculator does
The CO2 breathing emission calculator computes CO2 volume as breaths per minute times liters per breath times the exhaled CO2 fraction times minutes. It then multiplies that volume by an entered gas density to get a mass. In the worked example, 12 breaths per minute, 0.5 liters per breath, 4 percent CO2, and 60 minutes give 14.40 liters, and a density of 1.842 grams per liter gives 26.52 g CO2. The breathing values, density basis, provenance, and uncertainty are all user-supplied scenario assumptions, and the page states the result is not a personal footprint or a medical estimate.
The meat footprint calculator computes food mass as servings times kg per serving, then multiplies by an entered kg CO2e-per-kg lifecycle factor. In the worked example, ten 0.1 kg servings total 1.00 kg, and an entered factor of 27 kg CO2e/kg gives 27.0 kg CO2e. The factor’s food, dataset version, geography, and system boundary must be recorded with the result, and no water, land, car, or tree equivalent is inferred.
Side-by-side
| CO2 breathing emission calculator | Meat footprint calculator | |
|---|---|---|
| Inputs | Breaths/min, liters/breath, CO2 fraction, duration, gas density | Servings, kg per serving, kg CO2e-per-kg lifecycle factor |
| Calculation | Volume = rate × tidal × fraction × minutes; mass = volume × density | Food mass = servings × kg/serving; emissions = mass × factor |
| What the number means | Exhaled CO2 gas mass under entered physiology and density assumptions | CO2-equivalent emissions for an entered food serving scenario |
| Output units | Grams of CO2 (e.g. 26.52 g CO2) | Kilograms of CO2e (e.g. 27.0 kg CO2e) |
| Assumption handling | Physiology values, density basis, provenance, and uncertainty entered by the user | Factor metadata, provenance, and uncertainty entered by the user |
| Equivalents inferred | None | None — no water, land, car, or tree equivalents |
| Typical uses | Educational comparison of gas volume and mass | Dietary and food-purchasing scenario estimates |
When to use which
Use the CO2 breathing emission calculator when your question is about respiration itself — how much exhaled CO2 a breathing scenario produces as gas volume and mass, with the physiology and density basis made explicit. It is transparent gas arithmetic rather than a footprint, and its page directs readers to the meat footprint calculator, flight emissions calculator, and home energy efficiency calculator for scenario-style footprint estimates elsewhere.
Use the meat footprint calculator when your question is about food choices — how a number of servings at a serving size compares under a chosen lifecycle factor. Because the factor encodes food definition, geography, year, and system boundary, the calculator makes those assumptions visible and records them beside the result. Both pages treat scenario ranges as sensitivity ranges, not confidence intervals, and neither result establishes certification or compliance status.
Limits and disclaimer
Both pages are educational only and not personal carbon-footprint statements. The breathing calculator’s output depends entirely on entered physiology and density values, and the page notes it is not a medical estimate. The meat footprint calculator depends on the entered lifecycle factor, and its page requires matching food definition, geography, year, method, and lifecycle boundary before comparing factors across datasets. Treat scenario ranges as sensitivity ranges, not confidence intervals, and check the version, geography, and date of any entered factor before relying on the result.