Enter your area and the spacing between trees to see how many fit on a square grid, the row layout, and trees per acre.
The formula
On a square grid, trees per row = floor(length ÷ spacing) + 1 and the same for rows across the width; multiply the two for the total. Per-acre density is 43,560 ÷ spacing².
Worked example
A 100 × 60 ft area at 20 ft spacing fits 6 trees along the length and 4 across — 24 trees. At that spacing an acre carries about 108.
Choosing the spacing
Space for the mature canopy, not the sapling: two trees whose crowns will reach 20 ft across need 20 ft or more between trunks, and closer to 25 if you want daylight between them. Orchards on dwarfing rootstocks plant far tighter than shade trees; windbreaks tighter still, accepting interlocked crowns by design. Keep large species their mature-height distance away from foundations and septic lines, and remember a boundary row needs half a spacing of clearance to the property line so the canopy stays on your side.