Calculate post or pole counts and positions for straight runs, rectangular perimeters, or multiple independent runs using spacing supplied by your project design.
In maximum-spacing mode, the entered value is a user-supplied design limit. The calculator divides a run into enough bays that no calculated bay exceeds it; CalcRocket does not select the limit.
Exact and known-count layouts divide the run into equal bays. Posts and spaces are different: with both endpoints included on an open run, the number of posts is one more than the number of spaces.
spaces = ceil(run length ÷ spacing limit); posts = spaces + 1actual spacing = run length ÷ number of spacesunique posts = 2 × ceil(length ÷ spacing limit) + 2 × ceil(width ÷ spacing limit)cost = (calculated posts + spare posts) × price per postA 40 ft run with a user-entered 8 ft spacing limit and both endpoints uses 5 spaces and 6 posts.
A 42 ft run with a user-entered 8 ft limit uses 6 spaces and 7 posts. Placement from one end leaves a 2 ft final bay; even distribution uses six 7 ft bays.
A 50 ft run with 6 posts and both endpoints has 5 spaces at 10 ft.
A 20 × 12 ft rectangle with a user-entered 8 ft limit uses 3 spaces on each long side and 2 on each short side: 10 unique posts, including 4 corners.
Placement from one end steps at the entered limit. Even distribution keeps the same required bay count but divides the full run equally.
Choose whether a post exists at the start, end, both, or neither end.
Separate runs are independent. Subtract shared posts manually when two runs use the same physical post.
Add a whole-number spare allowance instead of percentage waste.
A from-one-end layout may have a shorter final bay. Even distribution removes that remainder by dividing the run into equal bays without exceeding the user-entered limit.
Each rectangle side is calculated independently. The closed-loop space count is also the unique post count, so four shared corners are not double-counted.
Run quantities are summed after inclusion settings. Because shared endpoints cannot be inferred, a project-level shared-post adjustment is explicit.
Post / Pole Spacing calculates positions and counts along runs. The Fence Calculator estimates a broader fence material system, while the Post Hole Calculator estimates excavation and material around posts.
The entered spacing limit is a layout assumption supplied by the user. CalcRocket does not determine structurally permitted spacing, post size, embedment, footing size, wind loading, or code compliance.
Divide run length by your project-supplied spacing limit, round spaces up, and add endpoints according to the layout.
For even spacing, divide the run length by the number of spaces.
With an 8 ft user-entered limit and both ends included, 40 ft needs 6 posts.
It depends on run length and endpoints; a 40 ft run with both ends uses 6. Verify that 8 ft is appropriate for your project before entering it.
Choose an appropriate space count, then divide the entire run by that count.
With both endpoints included on an open run, spaces equal posts minus one.
Each open interval sits between two endpoints, so five consecutive spaces require six boundary posts.
Placement from one end leaves a shorter final bay; even distribution makes every bay equal without exceeding the entered limit.
Calculate each side independently and count shared corners only once.
A simple closed rectangle includes four unique corner posts.
Yes. Add independent runs and manually subtract any shared physical posts.
No. Use spacing permitted by the project design, manufacturer, engineer, and applicable codes.
No. Use the Post Hole Calculator for concrete and gravel estimates.