How Many Fence Posts Do I Need? Formula and Examples
Count terminal posts first — ends, corners and two per gate — then fill each segment with line posts so no bay exceeds your spacing.
Use the fence post calculator →
The formula
- Terminal posts = end posts (2 for an open run, 0 for a closed loop) + 1 per corner + 2 per gate.
- Subtract gate widths from the total to get net fence.
- For each segment between terminal posts:
line posts = ceil(segment ÷ spacing) − 1.
Examples
- 100 ft straight, 8 ft spacing, no gates: 2 end posts; 100 ÷ 8 → 13 bays → 12 line posts. Total 14.
- 180 ft straight, 8 ft, two 4 ft gates: 172 ft net in 3 segments (~57.3 ft) → 8 bays each → 21 line posts + 6 terminal = 27.
- U-shape 50 + 100 + 30 ft, 8 ft, no gates: 2 end + 2 corner = 4 terminal; line posts 6 + 12 + 3 = 21. Total 25.
Buy one or two spare posts — crooked or split posts are common.
All figures are estimates based on baseline U.S. assumptions, not contractor quotes.