Tree Benefits Calculator
What a tree or a group of trees does over its life — carbon absorbed, air pollutants removed, stormwater intercepted and cooling provided.
A mature tree absorbs roughly 22 kg of CO₂ a year, though the range across species and conditions is wide.
How the tree benefits calculator works
A mature tree absorbs roughly 22 kg of CO₂ a year, though the range across species and conditions is wide. Over a 40-year life that is nearly a tonne per tree.
The carbon is often the least of it. Urban trees intercept stormwater, remove particulates, and cut summer cooling loads by shading buildings — that last effect alone can be worth more than the sequestration.
Formula: annual CO₂ ≈ 22 kg per mature tree
Worked examples
| Inputs | Lifetime CO₂ absorbed | Note |
|---|---|---|
| Ten medium trees over 40 years | 7,040 kg | 7 tonnes of CO₂ |
| Large species | 12,800 kg | nearly twice as much |
| A single tree | 704 kg | 700 kg over its life |
FAQFrequently asked questions
How much CO₂ does a tree absorb?
Roughly 22 kg a year once mature, though it varies from about 10 to 40 depending on species, climate and growing conditions.
How long until a tree is absorbing that much?
Typically 10 to 20 years. A newly planted tree absorbs very little, which is why offset schemes based on planting take decades to deliver.
Is planting trees a good offset?
It is slow, reversible and hard to verify. It is genuinely valuable — but as an addition to reducing emissions, never a substitute.
What else do urban trees do?
Intercept stormwater, filter particulates, and shade buildings. The cooling effect alone can cut summer air-conditioning use substantially.
Why does the survival rate matter?
Because urban planting has high mortality — 20 to 30% in the first few years is common. Counting planted trees rather than surviving ones overstates the benefit.
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
- US EPA — Greenhouse Gas Equivalencies Calculator — the official US equivalency factors
Last checked: September 2026. Factors are taken from published government and peer-reviewed sources, each named on the page with its year.