🪵 Tree Diameter Calculator
Quickly convert circumference measurements into DBH, a standard forestry metric for inventory and assessment.
How to Use This Calculator
Measure circumference
Wrap a diameter tape at 4.5 ft (1.37 m) height to obtain circumference.
Select the measurement unit
Switch between inches and centimeters as needed.
View DBH
Use the converted diameter for inventory, basal area, or tree appraisal calculations.
Formula
Diameter = Circumference ÷ π
Circumference should be measured at DBH height. Divide by π (≈3.1416) to convert to diameter.
Full Description
Diameter at breast height (DBH) is a foundational forestry measurement used to estimate tree volume, biomass, and age. Converting circumference to diameter saves time in the field when diameter tapes are unavailable.
Record both circumference and DBH for documentation, especially in long-term monitoring plots.
Frequently Asked Questions
What if the tree is on a slope?
Measure DBH from the upslope side at 4.5 ft above ground.
How do I handle irregular stems?
Take multiple measurements and average, or measure just above deformities.
Can I use this for multi-stem trees?
Measure each stem ≥4 in diameter and combine basal areas if needed.
Why use circumference instead of tape diameter?
Circumference is easier to obtain with standard tapes; conversion is quick using this tool.