Fence Materials & Concrete Calculator
Professional fence engineering & materials calculator. Estimate posts with topology corners and gates, frost-line concrete volume, pre-assembled panels or pickets, screws, and dynamic wind load rails.
Construction CalculatorsTopology & Perimeter Layout
Each gate opening adds dedicated heavy-duty gate posts and deducts opening width from infill.
Frost-Line Concrete & Footing
Includes 15 cm (6 in) crushed stone drainage pad below post bottom to prevent water stagnation.
Master Build Style
Wind Load Engineering Recommendation
3 Support Rails per Section (Recommended)Fence height exceeds 1.5 m (5.0 ft). 3 horizontal structural rails are required to prevent bowing and blow-over under lateral wind loads.
Dynamic Technical Blueprint SVG
Rotate your phone horizontally (landscape mode) for a clearer, full-detail blueprint view.
Contractor's Bill of Materials (BOM)
Always dig 15 cm (6 inches) deeper than the concrete requirement to install compacted crushed gravel. Never encase the very bottom of a wooden post in concrete—it traps standing groundwater and rots the core.
How to Use the Fence Materials & Concrete Calculator
Step-by-step guide to estimating posts, panels, pickets, frost-line concrete footings, and mortar for residential fences
Choose Unit System & Build Style
Toggle between Metric (m, cm, kg) and Imperial (ft, in, lb), then choose your construction style: Pre-assembled Panels, Vertical Pickets, Chain Link, or Brick Masonry.
Define Perimeter & Gate Openings
Enter total fence length, height, and post spacing (typically 2.0 to 2.5 m / 6 to 8 ft). Add 90° corners, single walk gates (1 m), and double driveway gates (3 m) to automatically deduct infill and add heavy-duty posts.
Set Frost-Line Depth & Hole Diameter
Specify auger hole diameter and depth, or choose regional frost line presets (Mild 60 cm, Moderate 90 cm, Severe 120 cm). The calculator accounts for a 15 cm drainage gravel base and post displacement.
Review Wind Load & Horizontal Rails
Inspect the automatic wind recommendation: fences taller than 1.5 m (5 ft) require 3 horizontal structural rails to resist lateral wind gust overturning.
Inspect 2D Blueprint & Bill of Materials
Toggle between top-down layout and elevation cross-section SVG views, and check required posts, concrete bags, gravel, rails, and fasteners.
Copy Material List for Contractor / Supplier
Click "Copy Material List" to save the complete lumber, hardware, and concrete bill of materials to your clipboard.
Frequently Asked Questions (FAQ)
Expert fencing engineering advice on frost heave prevention, hole sizing, post spacing, concrete volume, and wind resistance
Q:How deep should fence post holes be dug to prevent frost heaving?
Post holes must extend at least 15 cm (6 in) below your regional frost line (typically 60 cm in mild zones, 90 cm in moderate climates, and up to 120 cm in severe winter areas), and should equal at least 1/3 of the fence height above ground. Setting footings below frost depth prevents freezing ground moisture from heaving and tilting posts.
Q:What is the rule of thumb for post hole diameter and concrete volume?
A standard post hole diameter should be 3 times the width of the post (e.g., a 10×10 cm / 4×4 in post requires a 25–30 cm / 10–12 in diameter hole). Depending on depth, each post typically consumes between 2 and 4 bags of 25 kg (or 50 lb) pre-mixed concrete.
Q:Why is a gravel drainage pad essential at the bottom of the post hole?
Placing 15 cm (6 inches) of crushed gravel at the bottom of the hole allows groundwater to drain freely away from the end grain of wooden posts. Never encase the very bottom of a wooden post entirely in a concrete "cup", as it traps trapped water and rapidly rots the post core.
Q:What is the ideal spacing between fence posts?
Optimal post spacing is 1.8 to 2.5 meters (6 to 8 feet). Spacing posts wider than 2.5 meters causes horizontal rails to sag under the weight of pickets and dramatically increases the risk of wind failure. For heavy solid privacy fences or windy hilltops, 1.8 to 2.0 m (6 ft) spacing is strongly recommended.
Q:When do I need 3 horizontal rails instead of 2?
Any fence higher than 1.5 meters (5.0 ft) requires 3 horizontal support rails (top, middle, and bottom). Tall privacy fences act as large wind sails; a middle rail prevents vertical pickets from bowing inward or popping their fasteners under high aerodynamic pressure.
Q:How do gate openings affect the total post count and hardware?
Gate openings interrupt the continuous post grid. Each single pedestrian gate requires 2 reinforced gate posts (one hinge post, one latch post), while double gates require 2 heavy-duty terminal posts. The opening width (1.0 m for walk gates, 3.0 m for driveway gates) is deducted from the fence infill calculation.
Variable Definitions:
- L, S: Total perimeter length and post center-to-center spacing.
- D, Hdepth: Hole diameter and footing excavation depth below grade.
- Vpost: Solid volume displaced by the embedded post section.
- 1.10 Factor: 10% standard allowance for borehole wall irregularities and slump compaction.
- ⌈ x ⌉: Ceiling function (rounding up to the nearest whole integer).