Resin Anchor Calculator — Bore, Embedment & Cartridge Count

The bore diameter should be 2-4mm larger than the stud diameter: M8 = 10mm, M10 = 12mm, M12 = 14mm, M16 = 18mm, M20 = 24mm, M24 = 28mm. The annular gap between stud and bore is filled with resin. Too small a hole won't allow enough resin; too large reduces bond strength and wastes resin.

Minimum embedment depth depends on stud size and substrate. Typical minimum depths: M8 = 80mm, M10 = 90mm, M12 = 110mm, M16 = 125mm, M20 = 170mm, M24 = 210mm in solid concrete. Always follow the manufacturer's ETA (European Technical Assessment) for the specific product and substrate. In weaker substrates like solid brick, a common rule of thumb is to increase embedment by around 50% to offset the lower bond strength, but this is not a fixed standard — confirm the required bond length against the resin's ETA for masonry (which typically permit 4–20× the rod diameter), fill the hole completely and avoid setting the anchor in a mortar bed joint.

A standard 380ml resin cartridge yields approximately 29 fixes for M12 (13ml per fix), 15 fixes for M16 (24ml per fix), or 6 fixes for M20 (55ml per fix) — the calculator rounds down to whole fixes, since the resin left over at the end of a cartridge is not enough for a complete anchor. These per-fix figures are typical for vinylester/acrylic injection resin at standard embedment — epoxy resins and deeper embedments use more, so always check your cartridge’s stated yield. In practice, allow 10-15% waste for purging the nozzle and dead volume. The first few centimetres of each cartridge should be discarded to ensure proper mixing.

Cure time depends on temperature and product type. At 20°C: approximately 10-15 minutes for M8-M12, 20-30 minutes for M16-M20, 30-45 minutes for M24. As it gets colder the cure slows sharply — at around 5°C, cure times roughly double or more. For most standard vinylester/epoxy resins the practical minimum base-material temperature is about +5°C; below that the cure becomes impractically slow and full strength may not develop, so do not install below +5°C unless you are using a product specifically rated for cold weather (some manufacturers offer winter-grade resins certified down to −5°C or lower). Always check the resin's data sheet for its minimum installation temperature, and do not apply load until fully cured.

Yes, but you must use a perforated sleeve (mesh or nylon anchor sleeve) inserted into the hole first. The sleeve contains the resin and lets it key into the hollow cores through the perforations, creating a mechanical and chemical bond. The sleeve actually reduces resin loss into the voids and centres the rod — without one, the resin simply runs out through the hollow cores. The resin volume needed is roughly the internal volume of the sized sleeve, which can differ from the solid-concrete figure; this calculator applies a conservative void-filling allowance, so always confirm the fill volume against the sleeve datasheet. Check the manufacturer’s load data for hollow substrates. See our Block Calculator for block type information.