Size containers using trunk, canopy, time, and climate. See dimensions and easily estimated filled weight. Plant confidently today with fewer root problems later always.
Inputs use a responsive 3 / 2 / 1 column grid.
| Tree | Trunk (cm) | Height (m) | Canopy (m) | Years | Shape | Suggested volume (L) |
|---|---|---|---|---|---|---|
| Young citrus | 2.5 | 1.4 | 1.0 | 2 | Round pot | ~45 |
| Ornamental maple | 3.8 | 2.2 | 1.6 | 3 | Square planter | ~120 |
| Training bonsai | 1.2 | 0.6 | 0.4 | 1 | Round pot | ~10 |
This calculator combines two sizing signals, then applies adjustment factors. It returns a recommended container volume and suggests planter dimensions.
Constants are rules of thumb. Always check drainage and root health.
Trunk diameter is a fast proxy for woody mass and root demand. In this calculator, trunk-based liters scale with trunk_cm², which increases container needs quickly as trees thicken. A 3 cm trunk suggests a very different root volume than a 1.5 cm trunk, even if canopy looks similar. Use a steady measuring point about 15 cm above the soil line to keep results consistent across seasons. Record each value in your notes weekly.
Canopy spread correlates with leaf area, transpiration, and nutrient uptake. The canopy term uses canopy_m² to reflect that broader crowns dry containers faster and benefit from more buffered media volume. When your tree is pruned hard, canopy width can drop while roots remain active, so consider recent pruning and expected regrowth before choosing a smaller pot.
Keeping a tree potted for multiple years increases the risk of circling roots and moisture swings. The years factor adds 15% volume per extra year to reduce early root binding and to extend the repotting interval. If you plan to delay planting in-ground, selecting a slightly larger container improves stability and reduces heat stress in summer.
Volume alone is not enough; width and depth affect aeration and anchorage. Round pots use a cylinder model, while square planters use a box model. The depth-to-width ratio helps you match common nursery containers, shallow patio planters, or deeper training pots. If you set a maximum available width, the calculator increases depth to preserve volume.
Filled weight matters for balconies, transport, and tipping risk. The calculator estimates weight using potting mix bulk density and includes a small water allowance. For windy sites, prefer wider footprints, heavier pots, or added ballast. Always confirm drainage holes, keep the root flare visible, and step up one size if roots circle or water runs through too quickly.
Choose a wider container or add weight at the base. Increase the depth-to-width ratio only if width is limited. Stake lightly and avoid burying the trunk flare, which can cause rot.
Pruning reduces canopy temporarily, but roots often remain active. Keep the current container if root growth is strong, and reassess after regrowth. Down-sizing is rarely helpful for tree health.
Most young trees benefit from checking roots yearly and repotting every 1–2 years. If roots circle densely, media dries very fast, or growth slows, step up one size and refresh the mix.
Volume stays the same, but drying rate changes. Fabric and terracotta lose water faster than plastic. In hot or windy spots, consider adding 10–20% more volume or using mulched top dressing to reduce evaporation.
Use 0.45–0.65 kg/L for light mixes with bark and perlite, and 0.70–0.90 kg/L for heavier, compost-rich media. If unsure, keep 0.60 kg/L and adjust based on how heavy your pot feels.
Enter the largest pot width that fits your space. If the suggested width is larger, the calculator increases depth to keep the same volume. Confirm the final depth is practical for roots and drainage.
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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.