25 kg Concrete Calculator
This 25 kg concrete calculator converts your pour's dimensions straight into a bag count: one 25 kg bag yields about 12.5 litres (0.0125 m³) of mixed concrete, so the tool divides your volume by that yield and rounds up with waste.
Comment utiliser ce calculateur
- Saisissez vos dimensions — mètres pour les longueurs, centimètres pour l'épaisseur.
- Ajustez les options — pourcentage de perte, taille du sac et prix local du béton.
- Lisez vos résultats — le volume, les sacs, le poids et le coût se mettent à jour en direct.
La formule
Bags = volume ÷ 12.5 litres (0.0125 m³) per bag, rounded up (+5–10% waste) Exemple résolu : A 3 m × 3 m slab at 10 cm = 0.9 m³ → 0.9 ÷ 0.0125 ≈ 72 × 25 kg bags before waste.
The 25 kg bag dominates UK builders' merchants. For a concrete calculator 25kg bags estimate, the mixed yield is about 12.5 litres per bag — 80 bags per cubic meter. Postcrete-style rapid-set 25 kg bags yield slightly less; check the bag if you're setting posts.
Reference numbers for 25 kg bags: 62 bags make one cubic yard, 80 bags make one cubic meter. Keep those in your head at the store and you can sanity-check any estimate.
Bagged concrete makes sense up to roughly one cubic yard. Beyond that, price out ready-mix — mixing 45+ bags by hand is a full day of hard labor and the per-yard cost usually favors the truck.
Foire aux questions
Questions courantes sur le 25 kg concrete calculator.
How much concrete does a 25 kg bag make?
About 12.5 litres (0.0125 m³) of mixed concrete, per standard manufacturer yield data.
How many 25 kg bags in a cubic meter?
80 bags per cubic meter (1 ÷ 0.0125 m³, rounded up).
How many 25 kg bags for a fence post?
A 300 mm hole 600 mm deep needs ≈ 0.042 m³ — about 4 bags per post.
Should I add extra bags?
Yes — buy 5–10% more than calculated. Unopened bags return easily; a mid-pour shortage doesn't.
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