Arborvitae Tree Spacing Calculator and Planting Guide

An arborvitae spacing calculator estimates how many trees fit along a planting line and the center-to-center distance between them. Enter the planting-line length and the spacing you want; the calculator returns a practical tree count and the actual even spacing if you distribute that count evenly between the ends.

Formula

The number of trees placed at both ends of a straight line is n = floor(L / S) + 1. The even center-to-center spacing produced by that whole-number count is a = L / (n − 1). Here, L is the planting-line length in feet, S is the chosen target spacing in feet, n is the number of trees, and a is the actual spacing in feet. The floor function rounds down to a whole number.

This calculation assumes trees at both endpoints and at least two trees. The supplied defaults meet that condition. For a line shorter than the target spacing, the formula returns one tree, so the second output divides by zero; use a longer line or choose a different layout in that special case. It also assumes a straight row and equal spacing, not a curved boundary or staggered planting.

Worked Example

Using the calculator defaults, the line is 40 ft long and the target spacing is 4 ft.

1. Divide the length by the target spacing: 40 ÷ 4 = 10 intervals.
2. Add one tree because 10 intervals require 11 trees when both endpoints are planted: 10 + 1 = 11 trees.
3. Check the even spacing: 40 ÷ (11 − 1) = 40 ÷ 10 = 4.00 ft between centers.

The results are 11 trees and 4.00 ft of center-to-center spacing. Four feet equals 48 in, or approximately 1.22 m. In the calculator, enter all lengths in feet; convert metric measurements to feet first if necessary (1 m ≈ 3.281 ft).

How to Choose Arborvitae Spacing

Spacing depends on the mature width of the selected arborvitae, the job you want the row to do, and how much room is available. A tight hedge may need closer spacing for quicker visual coverage, while specimen trees generally need more space to develop their natural shape. There is no single spacing that suits every cultivar or site.

• Check the plant’s mature width. Use the expected width for the specific cultivar, not just its height or the size of the nursery plant. Mature dimensions vary considerably.
• Decide whether crowns should touch. For a continuous screen, gardeners often plan for neighboring crowns to meet or overlap slightly at maturity. For distinct, separate forms, leave a visible gap.
• Allow for maintenance and airflow. Crowded plants can be harder to access and may compete for light, water, and root space. A row that is too tight can become difficult to maintain as it grows.
• Consider the site. Soil drainage, sunlight, exposure, and available root space influence plant performance. Follow cultivar-specific growing guidance and local nursery recommendations.

For example, a 40 ft line at a 5 ft target spacing gives floor(40 ÷ 5) + 1 = 9 trees, exactly 5 ft apart. At 6 ft, it gives 7 trees, and even distribution across the same line makes their actual spacing 40 ÷ 6 = 6.67 ft. That difference matters: the calculator preserves the endpoints and spreads the selected whole number evenly, so actual spacing may differ from the target.

How to Use the Result in a Real Layout

Measure the actual planting line, not the full property boundary if trees cannot be planted at its ends. Decide how far each end tree should sit from a corner, fence, building, or other obstruction. Then calculate the usable distance between the first and last tree centers. If the end offsets are equal, subtract both offsets from the total line length before using the calculator.

Mark tree centers before digging. Measure from the center of one trunk position to the center of the next; spacing is not the clear gap between foliage or the distance between the edges of the root balls. For an irregular or curved boundary, measure the intended path in sections and check that the spacing remains appropriate around bends. A simple straight-line calculation cannot account for obstacles or changing row direction.

Spacing, Mature Size, and Common Mistakes

A frequent misconception is that spacing should be based on the trees’ current pot or root-ball size. That can produce a row that looks fine at planting but becomes congested as the crowns expand. Use the expected mature width as a starting point, then adjust for the desired hedge density and the cultivar’s recommendations.

• Do not confuse intervals with trees. Eleven trees in a row make ten spaces between neighboring trees. This is why the endpoint formula adds one.
• Do not mix units. A length in meters divided by a spacing in feet gives a meaningless count. Convert both values to the same unit first.
• Do not round the tree count up casually. More trees than the calculated count reduce the space between centers if both endpoints stay fixed.
• Do not assume the output guarantees a dense screen. Growth rate, plant health, cultivar, climate, and care all affect how quickly a hedge fills in.

If the result is one tree, the even-spacing output is undefined because there is no interval between two or more trees. That does not mean the tree is misplaced; it means this row-spacing formula is not useful for a single planting position. For two or more trees, the second output gives the exact equal interval implied by the chosen count.

Frequently Asked Questions

How far apart should arborvitae trees be planted?
It depends on the cultivar’s mature width and whether you want a continuous hedge or separate specimen trees. Check the plant’s mature-size information and use the calculator to compare possible row layouts rather than relying on one universal distance.

How many arborvitae do I need for a 40-foot hedge?
Choose a target center spacing first. At 4 ft spacing, 40 ft accommodates 11 trees when both ends are planted; at 5 ft spacing, it accommodates 9. Those figures assume no end offsets or obstructions.

Does spacing mean trunk-to-trunk or foliage-to-foliage?
It means center-to-center distance between planting positions, usually measured from trunk center to trunk center after planting. It is not the open gap between the outer foliage.

Should I plant arborvitae closer for a privacy screen?
Closer spacing can help crowns meet sooner, but planting too tightly can lead to crowding and difficult maintenance. Base the decision on mature width and cultivar guidance, and weigh quicker coverage against long-term growing room.

Can I use the calculator for a curved hedge?
Only as an estimate. Measure along the intended planting path and account for bends, end setbacks, and obstacles. For a strongly curved line, lay out the positions on the ground and check the intervals rather than treating the boundary as one straight line.

Related

• 1500m Lap Split Calculator: Pace and Lap Times
• 0–100 Calculator: Percentage, Score and Speed Uses
• Calculation Meaning & How to Use It

in L | Planting-line length | ft | 40 | 0
in S | Desired center spacing | ft | 4 | 0
out n | Number of trees | trees | floor(L / S) + 1 | 0
out a | Even center spacing | ft | L / (n - 1) | 2