Outdoor Projects calculator

Fence Post CalculatorFence Posts and Concrete Bags

Calculate fence post count from total fence length and post spacing, then estimate concrete bags using a user-entered bags-per-post value.

Updated August 20, 2026

✓Instant estimateNo sign-up required

✓Clear formulaSee how the result is built

✓Editable inputsMatch your product

✓Practical roundingPlan real purchase units

⌑

Project details

Enter your measurements and material details.

Planning estimate only. Verify product specifications and project requirements before ordering.

💡Tip:

Corners, ends and gate openings should be counted deliberately rather than relying only on even spacing.

How the Fence Post Calculator works

The basic post count is the fence run divided by spacing and rounded up, plus one end post. Extra gate or special posts can then be added. Concrete quantity uses the bags-per-post rate you enter.

Formula

Posts = ceil(fence length ÷ spacing) + 1 + extra posts. Concrete bags = posts × bags per post.

Measure before you buy

Measure the actual fence run along the layout line. If the fence changes direction, calculate runs separately or make sure corners are not double-counted. Gate posts are often larger or deeper than line posts.

Post depth and diameter depend on fence height, soil, wind and local requirements.
Gate posts may need more concrete than line posts.
Panel widths can control spacing more than a generic maximum spacing.

Common questions

How many posts for 100 feet of fence at 8-foot spacing?

About 14 posts for a simple straight run before extra gate or corner requirements.

Why add one post after dividing by spacing?

A run has posts at both ends, so the number of posts is typically one more than the number of spaces.

Does this calculate hole size?

No. Use the post-hole concrete calculator once hole dimensions are known.

Can gate posts use more concrete?

Yes. Calculate them separately or increase the bags-per-post value conservatively.

Does it calculate fence panels?

Use the fence calculator for panel or section planning.

Worked example: Fence Post Calculator

Using the example inputs shown in the calculator — Fence length (ft) = 120, Post spacing (ft) = 8, Concrete bags per post = 2, Extra gate posts = 2 — the result is 18 posts. This demonstrates the formula with a complete set of numbers rather than a hidden assumption.

The result breakdown also shows Fence run: 120 ft; Concrete bags: 36. Replace the example values with field measurements and the exact product coverage, yield or package size you plan to buy.

For this fence post calculator, the inputs with the greatest practical effect are fence length, post spacing and concrete bags per post. Recalculate when any of those change; do not reuse a result from a different room, run, layer depth or product specification.