Tree Spacing Calculator
A tree spacing calculator finds how many trees fill a row: row length ÷ spacing, rounded up, plus 1. A 100 ft row at 20 ft spacing takes 6 trees.
A tree spacing calculator tells you how many trees fit in a straight row. Divide the row length by the spacing, round any decimal up, and add one for the tree that starts the row. A 100 ft row with trees 20 ft apart has 5 gaps, so it takes 6 trees.
The formula in plain words
Picture a measuring tape laid along the row. Put a tree at 0 ft, then another every 20 ft: 0, 20, 40, 60, 80, and 100. That is 6 trees for 5 gaps.
The calculator does the same thing. It rounds the gap count up, then adds the tree at the start. If the gaps do not divide the row evenly, the last gap is shorter than the rest, so a tree still lands at the end of the row.
Spacing is measured from trunk to trunk, center to center, not edge to edge.
Worked examples
Example 1, the default: a 100 ft row, 20 ft spacing.
- Gaps: 100 ÷ 20 = 5
- Trees: 5 + 1 = 6
Example 2, spacing that does not divide evenly: a 100 ft row, 15 ft spacing.
- Gaps: 100 ÷ 15 = 6.67, rounded up to 7
- Trees: 7 + 1 = 8
- Trees stand at 0, 15, 30, 45, 60, 75, and 90 ft, and the 8th goes at 100 ft, 10 ft after the last
You can nudge the spacing to 16.7 ft to spread 7 trees evenly over the 100 ft, or to 14.3 ft for 8 evenly spaced trees. The calculator works on the spacing you enter.
Example 3, a grid: a 100 ft by 60 ft plot, 20 ft apart in both directions.
- Along the length: 5 gaps, 6 trees
- Across the width: 3 gaps, 4 trees
- Total: 6 × 4 = 24 trees
Trees per row
| Row length | Spacing | Trees |
|---|---|---|
| 60 ft | 10 ft | 7 |
| 100 ft | 25 ft | 5 |
| 100 ft | 20 ft | 6 |
| 100 ft | 15 ft | 8 |
| 120 ft | 8 ft | 16 |
| 200 ft | 30 ft | 8 |
How to pick the spacing
Look up the mature width of the tree you are planting. The nursery tag or a local extension office is a good source. As a starting point, trees are often spaced somewhere near their mature canopy width for an open look, and closer for a hedge or a windbreak.
Also consider what is around the row. Keep trees well away from buildings, septic fields, overhead wires, and underground utilities. Call your local utility marking service before you dig.
Common mistakes
- Forgetting the +1 and ending up one tree short.
- Planting for the sapling instead of the full-grown tree.
- Measuring from the property line when the row is meant to sit inside a setback.
- Planting under power lines with a tree that will grow tall.
- Using the open-row formula for a loop. A hedge that circles a yard needs perimeter ÷ spacing, with no +1.
Staggered rows and long runs
A windbreak row 300 ft long with 10 ft spacing has 30 gaps, so it takes 31 trees.
A staggered double row packs more in. Take the 100 ft row at 20 ft spacing. The first row has 6 trees at 0, 20, 40, 60, 80, and 100 ft. Offset the second row by 10 ft, and it has trees at 10, 30, 50, 70, and 90 ft, which is 5. Together that is 11 trees, with a tree every 10 ft along the length.
Check the price per tree and multiply by the count to budget the planting.
Planning around the roots and the crown
A tree needs space above and below ground. Roots usually spread wider than the crown, so keep trees away from foundations, drain lines, and paving. Check the height of the mature tree against overhead lines and nearby buildings. Mark the planting spots with stakes before digging, and step back to look at the row from the house and the street.
Related calculators
To budget the planting, use the tree planting cost calculator. The playground mulch calculator works out mulch for a play area under trees, and the fence post depth calculator covers posts along the same line. For ring mulch around each trunk, try the mulch calculator.
Frequently asked questions
How many trees do I need for a row of a given length?
Divide the row length by the spacing, round any decimal up, and add 1. A 100 ft row at 20 ft spacing has 5 gaps and 6 trees. A 100 ft row at 15 ft spacing has 6.67 gaps, which rounds up to 7, so 8 trees. The last tree sits at the 100 ft end, 10 ft after the tree at 90 ft.
Why do I add 1 to the row-length-divided-by-spacing number?
Gaps are counted between trees, and a row always has one more tree than gaps, like fence posts. Five gaps of 20 ft need 6 trees to mark both ends. Leave out the +1 and you would plant 5, ending one gap short.
How far apart should I space trees?
It depends on the species and the purpose. A hedge screen is planted close, a shade tree needs room for a large crown at maturity. Read the plant tag or ask the nursery for the mature spread of your tree, and set the spacing to fit. The calculator takes any spacing in feet.
What happens if I plant trees too close together?
As trees mature, their crowns and roots compete for light, water, and space, and they can grow lopsided or stay weak. Crowding is much harder to fix after planting than spacing correctly at the start. If you want a fast screen, plant at the close end of the nursery's range and plan to thin.
How do I plan a grid or orchard layout?
Work out each direction separately and multiply. A 100 ft by 60 ft plot at 20 ft spacing has ceiling(100 ÷ 20) + 1 = 6 trees along the length and ceiling(60 ÷ 20) + 1 = 4 across, for 24 trees.
Estimates only. Verify quantities with your supplier before purchasing.