Carbon Offset Cost Calculator
The cost of offsetting a quantity of greenhouse-gas emissions at a price per tonne — per year, per month and per kilogram — with a guide to what different prices buy.
Offsets are sold per tonne of CO₂-equivalent.
How the carbon offset cost calculator works
Offsets are sold per tonne of CO₂-equivalent. Prices span two orders of magnitude: cheap avoided-emissions credits (cookstoves, some forestry) sell for a few dollars a tonne, verified nature-based removals for tens, and engineered removal such as direct air capture for several hundred. Enter your emissions and the price you are considering; the calculator does the multiplication and puts the price in context.
Formula: cost = tonnes CO₂e × price per tonne
Worked examples
| Inputs | Cost per year | Note |
|---|---|---|
| 12 tonnes at 30 per tonne | 360 | 360 a year |
| A 2-tonne flight at 15 | 30 | 30 |
| Engineered removal: 5 t at 600 | 3,000 | 3,000 |
FAQFrequently asked questions
Do offsets actually work?
Some do and many have not: investigations have found large shares of forestry and avoided-deforestation credits over-claimed. Look for additionality, permanence, independent verification (Gold Standard, Verra with recent methodologies, Puro for removals) and a recent vintage — and reduce first.
Why do prices vary so much?
Because the credits are not the same product. Avoiding an emission somewhere cheap costs little; removing a tonne from the air and locking it away for centuries costs a lot. Price tracks permanence and verification more than anything.
How many tonnes should I enter?
A rough personal footprint is 5–20 tonnes a year depending on country and lifestyle; a return long-haul flight is about 2 tonnes per passenger; a petrol car doing 15,000 km about 3.5.
Is the cost tax-deductible?
Sometimes, when the seller is a registered charity, and never as a business expense in the way a carbon tax is. It depends on your country and the seller — the calculator makes no claim either way.
Where these figures come from
- UK DESNZ / DEFRA — Greenhouse gas reporting: conversion factors — the flight, fuel and waste emission factors used here
- Scarborough et al. (2014), Climatic Change — Dietary greenhouse gas emissions — the per-diet daily emission figures
- US EPA — Technical Assistance Document for the Reporting of Daily Air Quality (AQI) — the PM2.5 breakpoints the air quality calculator uses
- UK Department for Energy Security and Net Zero — conversion factors — the official UK emission factors
Last checked: September 2026. Factors are taken from published government and peer-reviewed sources, each named on the page with its year.