How the tree offset calculator works
Enter the amount of carbon dioxide you want to offset in tonnes per year, and the tool estimates how many trees would absorb that much carbon annually. It uses an average absorption rate per tree, which you can adjust, and also shows what offsetting over ten years would require.
How much carbon a tree absorbs
A commonly cited figure is that a typical maturing tree absorbs around 21 kilograms of carbon dioxide per year, though estimates range widely. Young trees absorb less, fast growing mature trees more, and the total a tree stores over its life depends on species, climate, soil, and whether it survives to maturity.
Why tree offsets are approximate
Real world offsetting is more complicated than a simple division. Trees take years to reach peak absorption, some die, and carbon is only stored while the wood remains intact. That is why these numbers are best treated as a rough sense of scale rather than a guaranteed offset, and why reducing emissions matters more than offsetting them.
Putting it in perspective
Seeing the tree count alongside an equivalent in car miles helps make a tonne of carbon tangible. Use it to understand the scale of an activity emissions, to plan a planting project, or to sanity check offset claims. Pair it with the carbon footprint calculator to estimate what you would be offsetting.
Frequently asked questions
How many trees offset a tonne of CO2? Very roughly 45 to 50 at about 21 kilograms absorbed per tree per year.
How much CO2 does one tree absorb? Often estimated near 21 kilograms a year for a maturing tree, but it varies widely.
Are tree offsets reliable? They are approximate; trees take time to mature and only store carbon while intact.
Related calculators: Carbon Footprint, Electricity Cost, Solar Panel.