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.

Bag size is locked to 25 kg for this calculator. Comparing sizes? Use the general concrete bag calculator.

m
m
cm
5%
$ pro m³

So verwenden Sie diesen Rechner

  1. Geben Sie Ihre Maße ein — Meter für Längen, Zentimeter für die Dicke.
  2. Optionen anpassen — Verschnitt in Prozent, Sackgröße und Ihr lokaler Betonpreis.
  3. Ergebnisse ablesen — Volumen, Säcke, Gewicht und Kosten werden live bei der Eingabe aktualisiert.

Die Formel

Bags = volume ÷ 12.5 litres (0.0125 m³) per bag, rounded up (+5–10% waste)

Rechenbeispiel: 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.

Häufig gestellte Fragen

Häufige Fragen zum 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.