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Tree Height Calculator

Estimate tree height using the shadow method with similar triangles or a clinometer angle reading.

Reviewed by Christopher FloiedPublished Updated

This free online tree height calculator provides instant results with no signup required. All calculations run directly in your browser — your data is never sent to a server. Enter your values below and see results update in real time as you type. Perfect for everyday calculations, homework, or professional use.

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Results

Estimated Tree Height

60 ft

How to Use This Calculator

1

Enter your input values

Fill in all required input fields for the Tree Height Calculator. Most fields include unit selectors so you can work in your preferred unit system — metric or imperial, whichever matches your problem.

2

Review your inputs

Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors and can produce results that are off by factors of 2, 10, or more.

3

Read the results

The Tree Height Calculator instantly computes the output and displays results with units clearly labeled. All calculations happen in your browser — no loading time and no data sent to a server.

4

Explore parameter sensitivity

Try adjusting individual input values to see how the output changes. This is a quick and effective way to develop intuition about how different parameters influence the result and to identify which inputs have the largest effect.

When to Use This Calculator

  • Use the Tree Height Calculator when you need accurate results quickly without the risk of manual computation errors or unit conversion mistakes.
  • Use it to verify calculations made by hand or in spreadsheets — an independent check can catch errors before they lead to costly decisions.
  • Use it to explore how changing input parameters affects the output — a quick way to develop intuition and identify the most influential variables.
  • Use it when collaborating with others to ensure everyone is working from the same numbers and applying the same assumptions.

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About Tree Height Calculator

The tree height calculator estimates the height of a tree using either the shadow method (similar triangles) or the clinometer angle method (trigonometry). Measuring tree height is fundamental in forestry, arboriculture, and ecology for timber volume estimation, hazard assessment, growth monitoring, and wildlife habitat evaluation. Direct measurement by climbing or tape is impractical for most trees, so indirect methods based on geometry are standard practice. The shadow method requires a sunny day and a reference object of known height, while the angle method uses a clinometer or inclinometer (often available as a smartphone app) and a tape measure for horizontal distance.

The Math Behind It

The shadow method relies on the principle of similar triangles: on a flat surface in direct sunlight, the ratio of any object's height to its shadow length is constant at a given moment. Therefore, H_tree / Shadow_tree = H_object / Shadow_object, and solving for H_tree gives the tree height. This method assumes flat ground, no shadow distortion from slopes, and that both shadows are measured at the same time (the sun's angle changes continuously). The angle method uses basic trigonometry: the tangent of the angle of elevation equals the opposite side (height above the observer's eye) divided by the adjacent side (horizontal distance). Adding the observer's eye height gives the total tree height from ground level. For trees on slopes, corrections must be applied: measure the angle to both the top and the base of the tree, and use the difference of the two tangent calculations times the distance. Professional foresters often use a hypsometer, which combines angle measurement and distance estimation (via rangefinder) in a single instrument.

Formula Reference

Shadow Method

H_tree = (Shadow_tree / Shadow_object) × H_object

Variables: H = height; Shadow = shadow length; uses similar triangles

Angle Method

H_tree = D × tan(θ) + eye height

Variables: D = horizontal distance; θ = angle to tree top; eye height = observer's eye above ground

Worked Examples

Example 1: Shadow method

A 6-ft person casts a 4-ft shadow. The tree's shadow is 40 ft.

Step 1:Ratio = 40 / 4 = 10.
Step 2:Tree height = 10 × 6 = 60 ft.

The tree is approximately 60 feet tall.

Example 2: Angle method

From 100 ft away, the angle to the top is 45°. Eye height is 5.5 ft.

Step 1:tan(45°) = 1.0. Height above eye = 100 × 1.0 = 100 ft.
Step 2:Total height = 100 + 5.5 = 105.5 ft.

The estimated tree height is about 105.5 feet.

Common Mistakes & Tips

  • !Measuring the shadow on uneven ground, which distorts the calculation.
  • !Forgetting to add eye height when using the angle method.
  • !Measuring the slope distance instead of horizontal distance when the tree is on a hill.

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Frequently Asked Questions

Which method is more accurate?

The angle method with a good clinometer and rangefinder is generally more accurate (±2–5%). The shadow method is simpler but requires flat ground and a clear shadow, and accuracy depends on precise shadow-tip identification.

Can I use my phone as a clinometer?

Yes, many smartphone apps use the built-in accelerometer to measure angles of elevation. Hold the phone edge-on, sight along the edge to the tree top, and read the angle. Accuracy is typically within 1–2 degrees.

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