Fence post materials list and Postcrete calculator

Item	Quantity	Where the figure comes from
Timber posts, 100 x 100 mm, pressure treated to Use Class 4, 2.4 m long	6	Height above ground plus at least 600 mm. Jacksons Fencing post length guide.
Postcrete or similar post fixing mix, 20 kg bags	12 bags	Two bags per 100 mm post in a 300 x 600 mm hole. Tarmac Blue Circle Postcrete datasheet.
Gravel or hardcore, 10 to 20 mm	42 litres	About 7 litres per hole for a 75 mm bed in a 300 x 300 mm hole, rounded up. A 20 kg bag is roughly 12 to 14 litres.
Timber off-cuts for bracing, about 1.2 m, plus screws	12	Two per post, one on each of two adjacent faces. Reusable from post to post once the mix has set.
End grain preservative, for any cut ends	1 tin	Treat every cut; keep the factory end in the ground. Jacksons Fencing; Alsford Timber Use Class guide.

Tools

Post hole digger (clamshell) or narrow spade

Digging bar, for stones and roots

Tape measure

Post level or spirit level

String line and two pegs

Bucket for spoil, watering can or hose

Waterproof, alkali-resistant gloves

Eye protection to EN 166

Wet cement burns, and the burn develops without pain being felt. Tarmac safety data sheet; HSE cement guidance.

From firstfixuk.com/materials/how-to-install-a-fence-post-with-postcrete/. Planning rules shown are for England; Scotland and Wales differ.

Setting fence posts: materials list and Postcrete calculator