Estimator notes
How this estimator works
Estimate line, terminal, corner, and gate posts for a straight, rectangular, or custom-segment fence layout. The formula is deterministic, keeps intermediate precision, and rounds only when a material must be purchased in a whole unit.
Typical planning scenarios
- A 100-foot straight fence with two ends.
- A four-sided rectangular yard enclosure.
- Custom segments with an extra gate.
Prices are optional. The quantity result still works when every price field is left empty.
Five solved numerical examples
These expected results were checked from the written arithmetic and are also fixed inputs to the golden-test suite. Comparable calculator checks and domain-expert review remain pending.
1. 100 ft straight fence
Expected result
- Line posts
- 12
- Terminal / end posts
- 2
- Corner posts
- 0
- Gate posts
- 0
- Total posts
- 14
Manual derivation
- 100 ft / 8 ft = 12.5, so round up to 13 equal spans.
- Thirteen spans require 12 line posts between two terminal posts, giving 14 total.
2. 8 m fence with one spare
Expected result
- Line posts
- 3
- Terminal / end posts
- 2
- Corner posts
- 0
- Gate posts
- 0
- Extra posts
- 1
- Total posts
- 6
Manual derivation
- 8000 / 2000 = four spans, requiring three line posts plus two ends.
- Adding one spare produces a purchase total of six.
3. Two exact spans sharing a corner
Expected result
- Line posts
- 0
- Terminal / end posts
- 2
- Corner posts
- 1
- Gate posts
- 0
- Total posts
- 3
Manual derivation
- Each section equals the maximum spacing, so neither requires a line post.
- The common endpoint is one corner: two terminals + one shared corner = three posts.
4. 6 m by 4 m rectangular fence
Expected result
- Line posts
- 6
- Terminal / end posts
- 0
- Corner posts
- 4
- Gate posts
- 0
- Total posts
- 10
Manual derivation
- Each 6 m side uses three spans and two line posts; each 4 m side uses two spans and one line post.
- Six line posts plus four shared corners gives ten total.
5. 10 m fence with centered gate
Expected result
- Line posts
- 2
- Terminal / end posts
- 2
- Corner posts
- 0
- Gate posts
- 2
- Total posts
- 6
Manual derivation
- The gate creates two 4 m fenced runs; each divides into two spans and contributes one line post.
- Two end posts + two gate posts + two line posts = six.
Common mistakes to avoid
- Letting a span exceed your selected maximum.
- Counting gate posts as line posts.
- Omitting corners from a custom layout.
Frequently asked questions
Does this confirm a code or permit requirement?
No. This calculator provides a material-planning estimate only. It does not provide structural engineering, permit advice, building-code interpretation, footing-depth approval, installation instructions, or guaranteed quantities.
Can I use metric measurements?
Yes. Switch to metric mode and enter millimetres, centimetres, or metres. The formula uses the same normalized measurements.
Estimate disclaimer
Results are planning estimates. Actual material requirements vary by product, installation method, site conditions, waste, and local rules. Verify product instructions and local requirements. This tool does not determine structural safety, footing depth, permit requirements, installation requirements, or code compliance. Have critical work reviewed by a qualified professional.
Last reviewed: July 16, 2026.