POST SPACING + CONCRETE CALCULATOR
For panel fence, chain-link and pipe-railing projects — compute post count and the concrete volume needed for each footing in one step. Choose square or cylindrical holes, add extra posts for corners and gates, and get a C20/25 concrete mix breakdown ready for the site order.
Inputs
Logic used
posts = ⌈length / spacing⌉ + 1 + extra_posts
total_concrete = posts × single_hole_volume (+5 % waste)
For a square hole V = a² × h; for cylindrical V = π × (d/2)² × h. A 5 % site-waste allowance is added. One cubic metre of C20/25 concrete needs roughly 350 kg cement, 600 kg sand, 1,200 kg gravel and 175 L water.
Result
No calculation yet
Enter fence length, post spacing and hole dimensions; post count and concrete demand will appear here.
Post spacing guide by fence type
Typical values averaged over dozens of field projects. In high-wind areas, on slopes or under snow load, reduce spacing by ~0.5 m.
| Fence type | Spacing | Post section |
|---|---|---|
| 2D panel fence (1.83 m) | 2.5 m | 40 × 60 × 1.5 mm |
| Chain-link mesh, 2.0 m | 3.0 m | Ø48 × 2.0 mm |
| Plain barbed wire line | 3.0 – 4.0 m | L60 × 60 × 6 mm or Ø48 |
| Hand-railing / wrought iron | 2.0 m | 40 × 40 × 2.0 mm |
| Heavy industrial perimeter | 2.0 m | 60 × 80 × 2.0 mm |
Recommended hole sizes by post type
Footing size depends on wind load, soil class and post height. In clay or loose ground add 100 – 200 mm to the depth.
| Post type | Hole (a / ⌀) | Depth |
|---|---|---|
| 40 × 60 box post (panel fence) | 300 × 300 mm | 600 mm |
| Ø48 tube post (chain-link) | ⌀ 300 mm | 500 mm |
| 60 × 80 box post (industrial) | 400 × 400 mm | 800 mm |
| Gate post (heavy hinge) | 400 × 400 mm | 800 – 1000 mm |
| Corner / brace post | 350 × 350 mm | 700 mm |
C20/25 concrete mix (per m³)
Standard footing mix compliant with EN 206. Compact with a poker vibrator or steel rod during pour. Without vibration, C16/20 is also acceptable for fence footings.
| Component | Amount |
|---|---|
| Cement CEM II 42.5 | 350 kg |
| Sand (0 – 4 mm) | 600 kg |
| Gravel (4 – 16 mm) | 1,200 kg |
| Water | 175 L |
| Water / cement ratio | ≈ 0.50 |
Where is it used?
The core sizing tool for post layout and concrete orders across panel fence, chain-link, barbed wire, gate and railing projects. These figures validate excavation and pump-truck requests when preparing a take-off.
Installation note
Plumb each post with a level and brace if necessary; do not remove the braces before 24 hours of curing. Over-sizing corner and gate footings by one step is the cheapest insurance against 3 – 5 years of ground settlement.
