Fence Post Concrete Calculator UK
Calculate how much concrete you need to set fence posts - Postcrete / post-mix bags, dry-mix bags or ready-mix. Enter your post count, hole dimensions and post size for a full material estimate.
Post and hole details
Typical: 200–300mm
Minimum 600mm for most fence posts
Check your product packaging
Covers cuts, breakages and uneven ground. 10% is a typical starting point.
Fence post concrete estimate
Enter number of posts and hole dimensions
How to calculate concrete for fence posts
The calculation subtracts the post volume from the hole volume to get the net concrete needed per hole, then multiplies by the number of posts. The method is the same whether you are using Postcrete bags, dry-mix or ready-mix.
For Postcrete and bagged mixes, the result is divided by the bag yield to give a bag count. For ready-mix, the total volume is rounded up to the nearest 0.25 m³.
Related calculators
Calculate how many fence panels, posts, gravel boards and Postcrete bags you need for a garden fence.
Calculate how many bags of Postcrete you need per fence post.
Work out how much concrete you need for a shed base, garage base or garden room.
Work out gravel in tonnes and bulk bags for driveways, paths and garden borders.
Frequently asked questions
Planning estimates only
These results are estimates for planning purposes only. Actual material quantities can vary based on site conditions, compaction, wastage, product size, installation method and supplier guidance. For structural, safety-critical or regulated work, always consult a qualified professional.