Tree Offset Calculator
Calculate how many trees you need to plant to offset a given amount of CO₂ emissions per year.
How it works
- 1Enter the total CO₂ you want to offset in kilograms per year.
- 2Set the CO₂ absorbed per tree per year — the default of 21 kg is a widely used long-run average for a mature tree.
- 3The calculator divides your emissions by the per-tree absorption rate and displays the number of trees needed.
Use cases
- Estimate how many trees a business must plant to reach carbon-neutral operations.
- Plan reforestation projects to compensate for a household or event carbon footprint.
- Compare the impact of different tree species by adjusting the absorption rate.
Frequently asked questions
How is the number of trees calculated?
Trees needed = CO₂ (kg/year) ÷ absorption per tree (kg/year). For the default values: 1 000 kg ÷ 21 kg ≈ 48 trees. Change the absorption field to model faster-growing species.
Why is 21 kg the default absorption rate?
A mature broadleaf tree sequesters roughly 21 kg of CO₂ per year on average over its lifetime. Young saplings absorb far less, so real projects often use a higher tree count to account for early-growth periods.
Does the calculator account for the age of the trees?
No — it uses a single long-run average. Young trees absorb only 1–5 kg/year, while mature trees may absorb 20–50 kg/year. For conservative planning, reduce the absorption rate or increase the tree count by 50–100 %.
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