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

727.525 lb

Net measurement: 661.387 lb · Waste 10 %

Net dry mortar661.387 lb
55.116 lb bags14 bag

Use my prices

Your prices per language/currency. Used when you enable “Use my prices” in calculators. My prices →

Calculate labour, margin & GST

Shopping list

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

55.116 lb 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

Add labour, overhead and your margin, and generate the professional PDF.

Create quote Calculate margin & GST

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.