About the Tree Height Calculator
This tree height calculator estimates the height of a tree from the ground using three classic field methods. The shadow method compares the tree’s shadow with the shadow of an object of known height; the clinometer method uses the angle from your eye to the treetop and your distance from the trunk; and the stick (or "woodsman’s") method uses a stick held at arm’s length and similar triangles.
It is handy for homeowners deciding whether a tree could reach the house if it fell, for planning removal or pruning quotes, for checking clearance under power lines and for school and scouting projects. Foresters use the same trigonometry with professional hypsometers.
All three methods assume the tree is roughly upright and the ground is fairly level. Measure distance to the trunk, not the edge of the canopy, and work in a single unit (feet or meters) throughout. For leaning trees or slopes, take readings from two sides and average them.
With the default inputs, the estimated tree height is 45. Change any value above to recalculate instantly.
How to use the tree height calculator
- 1Choose a method: shadow on a sunny day, angle with a clinometer or phone app, or the stick method.
- 2Pick feet or meters and use that unit for every measurement.
- 3Measure from the base of the trunk, not the canopy edge.
- 4Enter your readings and read off the estimated height.
- 5Repeat from another side and average the results for leaning trees.
Formula and method
The shadow method relies on the sun’s rays hitting the tree and the reference object at the same angle, so their heights are in the same ratio as their shadows. Measure both shadows within a few minutes of each other.
The clinometer method forms a right triangle: the tangent of the angle to the treetop equals the height above your eye divided by your horizontal distance to the trunk, so you add your eye height at the end. The stick method uses similar triangles — a stick of length s held vertically at reach a spans the same view as the tree of height H at distance d, so H = d × s ÷ a.
- H
- Tree height
- d
- Horizontal distance from you to the trunk
- θ
- Angle from your eye up to the treetop
- s, a
- Stick length and eye-to-stick distance
Worked examples
Shadow method with a 6 ft pole
A 6 ft pole casts a 4 ft shadow, so every foot of shadow equals 1.5 ft of height. The tree’s 30 ft shadow means it is 30 × 1.5 = 45 ft tall. The sun is about 56° above the horizon.
Clinometer reading of 40° from 50 ft away
tan(40°) ≈ 0.839, so the treetop is 50 × 0.839 ≈ 41.95 ft above your eyes. Adding a 5.5 ft eye height gives about 47.5 ft.
Stick method in meters
A 0.6 m stick held 0.65 m from the eye exactly spans the tree when you stand 18 m away, so the tree is 18 × 0.6 ÷ 0.65 ≈ 16.6 m tall — about 54.5 ft.
Frequently asked questions
How can I measure a tree’s height without tools?+
Use the stick method: hold a stick vertically at arm’s length so the part above your hand equals your arm length, then walk back until it spans the tree from base to top. Your distance to the trunk is then about the tree’s height.
How accurate is the shadow method?+
On level ground with a crisp shadow tip it gives a good estimate, and the main errors come from finding the exact tip of the tree’s shadow and from sloping ground. Measure both shadows within a few minutes of each other, avoid the long, fuzzy shadows near sunrise and sunset, and repeat on another day to check.
Can I use my phone to measure tree height?+
Yes. A level or clinometer app reads the angle to the treetop. Combine it with your measured distance to the trunk and your eye height: height = distance × tan(angle) + eye height.
What is the 45-degree rule for tree height?+
If you stand where the angle to the treetop is 45°, the height above your eye equals your distance to the trunk, because tan(45°) = 1. Add your eye height to get the full tree height.
How far could a tree fall?+
A falling tree can reach roughly its full height from the trunk, and debris travels further. Arborists typically clear a zone of about 1.5 times the tree height when felling.