This estimates quantities; strength class follows the design by use.

How much mortar for a wall?

Area × consumption (per thickness) ÷ bag. Example: 215 sq ft at 3.1 lb/ft² → about 15 × 50 lb bags with 10% waste.

How many bags for 215 sq ft of render?

At 15 kg/m² (≈3.1 lb/ft²): 300 kg net, 330 with waste → 14 × 25 kg bags (or 15 × 50 lb).

Same consumption for every thickness?

No: thicker coats need more per sq ft. Set consumption to your real coat thickness.

Can I see pounds per square foot?

Yes — switch to Imperial: 15 kg/m² shows as ≈3.1 lb/ft² and a 25 kg bag as ≈55 lb.

Mortar calculator

Dry-mix mortar bags by area (masonry/render) or by volume.

Purchase quantity

330 kg

Net measurement: 300 kg · Waste 10 %

Net dry mortar300 kg
25 kg bags14 bag

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Shopping list

What to buy for this calculation. Look up each material at your store.

25 kg bags · 14 bagSearch at Amazon

How it's calculated (visible formula)

kg = m² × kg/m²; bags = ceil(kg × (1+waste) ÷ bag)

Net geometric measurement, no waste.
Adjustable waste % for cuts and breakage.
Purchase rounded up to sellable units (boxes, bags, buckets, boards).

See methodology and formula versions

Worked example: 20 m² render at 15 kg/m²

300 kg net
+10% → 330 kg

→ 14 × 25 kg bags (350 kg).

Common mistakes

One consumption for every thickness.
Mixing too much ahead of pot life.

From calculation to quote

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FAQs

Which mortar class?: This estimates quantities; strength class follows the design by use.
How much mortar for a wall?: Area × consumption (per thickness) ÷ bag. Example: 215 sq ft at 3.1 lb/ft² → about 15 × 50 lb bags with 10% waste.
How many bags for 215 sq ft of render?: At 15 kg/m² (≈3.1 lb/ft²): 300 kg net, 330 with waste → 14 × 25 kg bags (or 15 × 50 lb).
Same consumption for every thickness?: No: thicker coats need more per sq ft. Set consumption to your real coat thickness.
Can I see pounds per square foot?: Yes — switch to Imperial: 15 kg/m² shows as ≈3.1 lb/ft² and a 25 kg bag as ≈55 lb.

Maintained by Srikanta M · Formula v1.0.0 · Verified 2026-09-10 · Updated 2026-09-10 · Limits: quantity estimation, not structural design or site supervision.