Have you ever wondered how long that massive oak in your backyard has been growing? Our free Pro Tree Age Calculator is the most comprehensive tool available online for estimating the history of your landscape. We have expanded our database to include 126 different tree species, each with scientifically researched growth factors. Whether you are measuring a common Maple or a rare Ginkgo, our tool provides an accurate estimate without the need for invasive core sampling or cutting the tree down.
We know that not everyone has professional forestry tools. That’s why we’ve made our calculator incredibly flexible. You can enter your measurements using circumference, diameter, or radius, and choose from five different units: inches, feet, centimeters, meters, or millimeters. This tool is 100% free, works instantly on any device, and is designed for homeowners, students, and nature lovers who want to connect with the history of the world around them.
Helpful Tips
Foresters measure at 4.5 feet (1.37 meters) above the ground. This "breast height" measurement is the global standard for tree age formulas.
Use the Unit Dropdown to switch between metric and imperial. The tool automatically converts your input to the correct scientific diameter.
A lower growth factor (like 2.0) means the tree grows quickly. A higher factor (like 7.0) means the tree grows very slowly and is likely much older than it looks.
Trees in open, sunny yards often grow faster than those in crowded forests. If your tree has lots of space, it may be slightly younger than the estimate.
Tree Growth Speed Reference Table
| Species Type | Growth Factor | Typical Speed | Common Examples |
| Pioneer Species | 2.0 - 2.5 | Fast | Aspen, Willow, Cottonwood |
| Urban Shade Trees | 3.0 - 4.0 | Moderate | Silver Maple, Elm, Sycamore |
| Hardwoods | 4.5 - 5.5 | Slow | White Oak, Sugar Maple, Beech |
| Legacy Trees | 6.0 - 7.5 | Very Slow | Shagbark Hickory, American Beech |