Tree Spacing Calculator

Background.

For two trees of the same kind, the usual extension answer to "how far apart?" is one mature canopy spread, trunk to trunk. Washington State University Extension's guide to spacing landscape plants puts it as half the combined spread of the two plants, which for a matched pair with 30-foot crowns is 30 feet: the distance at which the crowns will just meet once both are grown. The University of Florida's woody-plant pages make the same point. So the figure that sets the spacing is your tree's crown width at maturity, from the nursery tag or your extension office, and not the size of your land.

The land decides how many trees that spacing allows. Foresters and orchard growers turn spacing into density with one division, 43,560 square feet in an acre over the ground each tree occupies; that is how the University of Georgia and Penn State Extension build their trees-per-acre tables, in which 10 by 10 feet is 436 trees an acre and 12 by 20 feet is 182. For a real plot, the trees are laid out inside a setback from the boundary, and rows are tried running both ways to see which fits more.

The pattern changes the count more than most people expect. Offsetting alternate rows by half a spacing lets the rows close up to 0.866 of the tree spacing without bringing any two trees closer together, which fits 15.47% more trees per acre. On the default 200 by 120 foot plot that means 22 trees instead of 18 on a square grid.

What no spacing rule checks is whether a tree may go there at all: power lines, buried services, septic fields, sight lines and local ordinances set their own distances. In the United States, call 811 before you dig.

What is tree spacing calculator?

Tree spacing is the centre-to-centre distance between trunks, given within a row and between rows; a 12 by 20 planting has trees 12 feet apart along each row and rows 20 feet apart. Mature canopy spread is the crown's diameter when the tree is full grown, which is not the same as its height. A square grid uses one distance both ways, a rectangular grid widens the rows for access, and a triangular or staggered grid shifts every other row by half a spacing so each tree sits among six equally distant neighbours. Trees per acre describes an endless grid of that pattern; the count for a plot is a separate figure, because a plot has edges and a setback.

How to use this calculator.

1. 01Choose the pattern: triangular for the most trees at a given distance, rectangular when you need wide aisles for a mower or sprayer, square for a simple grid.
2. 02Enter the plot's length and width in feet, and the setback from the boundary to the first row of trunks, applied on all four sides.
3. 03To space from the tree, enter its mature canopy spread and the spacing as a percentage of it: 100% for crowns that just meet, around 50% or less for a screen or windbreak that should close up, more than 100% for space between crowns.
4. 04If an orchard plan or planting specification already gives the distances, choose to set the spacing yourself and enter the tree spacing, plus the row spacing for a rectangular grid. The mature spread is then used only to describe how the crowns will meet.
5. 05Read the count, the density and the crown verdict, then the layout note, which says how the rows run, what the other orientation would fit and what the result does not check.

The formula.

The in-row spacing is S = mature spread × percentage ÷ 100, or the distance you entered. Row spacing R equals S for a square grid, your own figure for a rectangular one, and S × √3 ÷ 2 = 0.866 × S for a triangular one, because three neighbouring trees form an equilateral triangle and the gap between rows is that triangle's height. Each tree occupies a cell of S × R square feet, so the density is 43,560 ÷ (S × R) trees per acre. Since √3 ÷ 2 shrinks the cell, a triangular grid carries 2 ÷ √3 = 1.1547 times the trees of a square grid at the same spacing. To count a plot, the setback is taken off both ends of each side to give the planting rectangle. The rows that fit across it are ⌊width ÷ R⌋ + 1, and the trees per row ⌊length ÷ S⌋ + 1; in a triangular grid every second row starts half a spacing in, so it holds ⌊(length − S ÷ 2) ÷ S⌋ + 1. Both orientations are counted and the larger is reported. Canopy cover is the crown area π × (spread ÷ 2)² of every tree as a share of the whole plot. The verdict compares S with the spread: under half, the crowns merge into a screen; from half up to the spread, they overlap; exactly equal, they just touch; beyond it, they stay apart. A setback that leaves no room to plant is rejected.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Coder, K.D. (2023). "Number of Trees per Acre by Spacing Distance." University of Georgia Warnell School of Forestry & Natural Resources, Outreach Publication WSFNR-23-02C, January 2023, 6 pp. Source of the stated formula — trees per acre = 43,560 / (spacing direction 1 x spacing direction 2) — and of Table 1 (square grid) and Table 2 (rectangular), including the worked 9x9 = 538 and 12x20 = 182 examples. Retrieved 2026-07-31; open access PDF, read in full.
2. [2]Penn State Extension. "Forest Landowners Guide to Tree Planting Success." Table 2, "Spacing by trees per acre" — 4x4 = 2,723 through 12x12 = 303 — with the stated method "multiply the planned spacing (in feet) within rows by the spacing (in feet) between rows and divide that number into 43,560, the number of square feet in an acre." Used as the independent check on the University of Georgia table: the two agree on all nine overlapping rows. Retrieved 2026-07-31; open access.
3. [3]Washington State University Extension, Spokane County Master Gardener Program. C132, "Spacing of Landscape Plants", revised 2015, format updated 2024. Source of the spacing rule — "For two different plants, placement from each other is one-half of the total spread for both plants" — and of the default boundary setback, "Strong-wooded shade trees, such as oaks, should be planted no closer than 20 feet from the house." Retrieved 2026-07-31; open access PDF, read in full.
4. [4]Gilman, E.F. University of Florida / IFAS Environmental Horticulture, "Spacing", last modified 24 January 2020. Independent confirmation of the mature-spread rule: "Trees are often spaced apart according to their mature canopy spread." Retrieved 2026-07-31; open access.
5. [5]Wells, L. University of Georgia Cooperative Extension Bulletin B 1314, "Establishing a Pecan Orchard." Table 1 gives orchard tree density from the same 43,560 / (in-row x between-row) formula, including 20 x 20 ft = 109 trees per acre. Used as a corroborating check on the rectangular case rather than as a primary source — only the 20 x 20 row was read directly. Retrieved 2026-07-31; open access.
6. [6]National Institute of Standards and Technology, Handbook 133 – 2026, Appendix E, "General Tables of Units of Measurement". Units of Area: 1 acre = 43,560 square feet exactly, the constant behind every density figure on this page. Retrieved 2026-07-31; open access PDF.