Fence Post Spacing: Count Runs, Corners and Gates
Avoid the extra-post surprises that come from treating your whole fence as one straight line.
Measure before dividing
Draw a rough layout and label every corner, endpoint and gate. A long perimeter measurement cannot show where a fence changes direction. Measure each straight run between planned post centers. A survey establishes property boundaries; a tape measurement does not.
Round the bays, not the total fence
For a 50 ft run with an 8 ft planning maximum, ceil(50 ÷ 8) gives 7 bays. Spacing them evenly gives about 7.14 ft per bay and 8 posts for that isolated run. Two separate 50 ft fences need 16 posts. If they join at one corner, they share one support and need 15.
The gate position changes the result
These examples measure gate spans between post centers, not the clear opening between the posts. A 100 ft run with a 4 ft support-center gate span at 48 ft leaves two 48 ft spans. Six bays on each side plus the gate interval give 14 unique posts. Put that same gate at 43 ft and the spans become 43 ft and 53 ft, requiring six and seven bays: 15 posts. Subtracting gate width and rounding only once misses this difference.
Pick spacing from the actual system
The 8 ft setting is a calculator example, not a structural recommendation. Rail length, fence height, wind, post strength, soil and manufacturer requirements can demand shorter spans. For rails mounted between posts, verify the actual cut length and attachment detail. A calculator is useful for quantities after the design requirements are established.
For the Clear opening input mode, the tool first adds the two half gate-post widths. Those adjusted support spans can change the bay and post counts. See the measurement diagrams.
Before the first hole
Review the pre-build checklist for setbacks, permits, HOA rules and utility checks. Match embedment and footing dimensions to local requirements and your selected fence system. A gate support carries loads that an ordinary line post may not.