Tree Age Calculator

Estimate a tree's age using trunk circumference or diameter, tree species, growth factor, and tree condition. This tree age calculator uses DBH, diameter at breast height, to estimate the age of standing trees without cutting them down.

Calculate Tree Age

Estimated Tree Age = Diameter in Inches × Growth Factor.
Your result will appear here.

How the tree age calculator works

Diameter method:
Enter the trunk diameter, choose a tree species or growth factor, and the calculator multiplies diameter by the growth factor.

Circumference method:
Enter trunk circumference and the calculator converts it to diameter using circumference divided by π.

Condition adjustment:
The calculator can adjust the estimate for faster open-area growth, slower forest growth, or poor soil conditions.

Age range:
Because tree growth varies, the calculator also shows a low and high estimated age range.

Why use a tree age calculator?

A tree age calculator helps estimate the age of a living tree without cutting it down or counting growth rings.

It can be useful for homeowners, gardeners, arborists, nature projects, forestry education, landscaping, tree records, and estimating the age of large shade trees.

What your result means

Your result shows estimated tree age, trunk diameter, trunk circumference, growth factor, adjusted age, low age estimate, high age estimate, and the measurement method used. The result is an estimate because tree growth depends on species, climate, soil, sunlight, water, crowding, disease, pruning, and local growing conditions.

Tree age formulas

Frequently asked questions

How do you estimate the age of a tree?

Measure the trunk diameter about 4.5 feet above the ground, then multiply the diameter in inches by the tree species growth factor.

What does DBH mean?

DBH means diameter at breast height. It is usually measured about 4.5 feet above the ground.

Is this tree age calculator exact?

No. It gives an estimate. The only way to know the exact age of many trees is to count growth rings, but that usually requires a cut stump or core sample.

Why do different trees use different growth factors?

Tree species grow at different speeds. Fast-growing trees usually need a lower factor, while slow-growing trees usually need a higher factor.