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Basal Area Calculator
Calculate one tree's basal area from diameter at breast height in inches or centimetres.
Basal Area Calculator
Calculate the circular cross-sectional area of one tree from its diameter at breast height (DBH).
Basal area per tree
Enter the tree's DBH.
This calculator covers one tree only. It does not estimate stand basal area per acre or hectare.
Formula version 1.0.0
How to use this calculator
- Measure one tree's diameter at breast height (DBH).
- Choose inches or centimetres to match the measurement.
- Enter the positive DBH and calculate.
- Read the circular stem area in square feet and check the converted value.
Symbols and units
| Symbol | Meaning | Unit or domain |
|---|---|---|
DBH | Diameter at breast height | in or cm |
r | Stem radius | in |
BA | Basal area of one tree | ft² |
Checked examples
Ten-inch tree
Inputs: DBH 10 inches
Calculation: π×(10÷2)² = 25π in²; divide by 144
Result: ≈0.545415 ft²
This is the cross-sectional area of one idealized circular stem.
Check: basal-area.test.ts
Equivalent metric input
Inputs: DBH 25.4 cm
Calculation: 25.4 cm = 10 in, then apply the same circle formula
Result: ≈0.545415 ft²
Unit conversion preserves the physical area.
Check: basal-area.test.ts
Assumptions, rounding, and limits
- DBH is positive.
- The stem cross-section is treated as circular.
- The calculation is for one tree, not stand basal area per acre or hectare.
- Measurement height and forestry conventions must follow the applicable field protocol.
Frequently asked questions
What is DBH?
It is stem diameter measured at a standardized breast height defined by the field protocol.
Does this calculate stand basal area?
No. It returns one tree's area; stand estimates also require sampling or tree counts.
Why is the result in square feet?
The calculator normalizes either supported DBH input unit to a common forestry area output.
Sources and review
- University of Georgia Warnell School of Forestry and Natural Resources: Calculating Basal Area per Unit Area — Basal area from DBH
- Formula version
- basal.area@1.0.0
- Formula review
- Equatara formula review
- Editorial review
- Equatara editorial review
- Last verified
- 2026-10-25
- Applicability
- Single-tree circular basal area; not a stand inventory estimate.
- Next review
- On material formula/source change, or by 2028-10-25.
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Found a problem?
Report a formula, result, example, source, or accessibility issue through the calculator correction process. Do not include sensitive input values.