Free Fence Calculator for Posts, Sections, Pickets, Rails, Gate Openings, Spacing, and Waste
Use this browser-side calculator to turn measurements and material assumptions into a practical first-pass estimate. Review the formula, replace defaults with real product data, and verify project requirements before purchasing or building.
Use the calculator
How to use this calculator
1. Measure consistently
Use the units shown beside each field and recheck the dimensions that drive the calculation.
2. Replace defaults
Use actual package coverage, spacing, waste, density, pitch, or product dimensions whenever they are known.
3. Verify before ordering
Compare the result with drawings, manufacturer data, supplier units, code requirements, and site conditions.
12 useful features
Total fence run
Built into this calculator for a clearer planning workflow.
Max post spacing
Built into this calculator for a clearer planning workflow.
Gate-opening subtraction
Built into this calculator for a clearer planning workflow.
Baseline post count
Built into this calculator for a clearer planning workflow.
Section count
Built into this calculator for a clearer planning workflow.
Average section length
Built into this calculator for a clearer planning workflow.
Picket width and gap
Built into this calculator for a clearer planning workflow.
Waste-adjusted pickets
Built into this calculator for a clearer planning workflow.
Rail-row selector
Built into this calculator for a clearer planning workflow.
Stock-rail equivalent
Built into this calculator for a clearer planning workflow.
Local history
Built into this calculator for a clearer planning workflow.
Copy/download/print/reset
Built into this calculator for a clearer planning workflow.
Formula and reference table
| Concept | Formula / meaning | Planning note |
|---|---|---|
| Fence sections | ceil(total run ÷ max post spacing) | Simple straight-run baseline |
| Baseline posts | sections + 1 | Extra gate/corner posts may be required |
| Pickets | picketed length ÷ (picket width + gap) | Then waste and whole-unit rounding |
| Rail footage | picketed length × rail rows | Then waste |
Pre-order checklist
0 / 5 complete
Quick knowledge check
What is the safest way to use a construction calculator?
Microlearning guide
Geometry is one layer
A correct area, volume, spacing, or slope formula does not replace structural, product, installation, or code requirements.
Whole units matter
Bricks, bags, rolls, cases, and stock pieces are purchased as discrete units, so planning often requires rounding upward.
Assumptions drive results
Waste, joint size, spacing, pattern repeat, product coverage, or selected layout can change the estimate more than extra decimal places.
Examples and practical uses
Early planning
Compare quantity scenarios before requesting material quotes.
Purchase cross-check
Compare the calculated quantity with package coverage, stock lengths, or supplier recommendations.
Formula review
Use the reference table to independently reproduce the main arithmetic.
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Frequently asked questions
Does the post count include special gate and corner posts?
No. It is a baseline for a simple continuous run. Gates, corners, braces, terminals, and changes in direction can require additional posts.
Why are gate openings subtracted from pickets and rails?
The entered combined gate width is treated as an opening in the regular fence infill. Gate frames, rails, pickets, and hardware must be estimated separately.
Can I estimate privacy-fence pickets?
Yes. Enter the actual picket face width and planned clear gap. For overlapping or board-on-board layouts, a different coverage method is needed.
Does the tool calculate post-hole concrete?
No. Use a concrete or Sonotube calculator after determining hole dimensions and the project-specific post installation details.
Does this determine legal fence height or setback?
No. Height, setbacks, permits, wind requirements, and property-line rules depend on local requirements and project conditions.