What is the difference between mortar dry factor 1.33 and concrete 1.54?

Mortar (cement + sand only) uses a dry-volume factor of 1.33: V_dry = V_wet × 1.33. RCC concrete (cement + sand + aggregate) uses 1.54. The difference is because mortar has no coarse aggregate — fine particles compact more predictably and less air-void reduction occurs. Using 1.54 on a mortar order would over-estimate cement and sand by about 16%. This calculator uses 1.33 for all mortar calculations, consistent with CPWD analysis of rates and standard Indian QS practice.

Which cement to sand ratio should I use for brickwork mortar in India?

IS 2212:2003 (Code of Practice for Brickwork) guidance: 1:3 (cement:sand) for external masonry or severe exposure; 1:4 for general protected load-bearing brickwork — the most common residential site specification; 1:5 for partition walls and non-load-bearing fillers; 1:6 for very lightly loaded non-structural work. This calculator defaults to 1:4. For plastering specifically (thin coats), 1:3 is common for scratch/base coats and 1:6 for finish coats.

How many cement bags per cubic metre of mortar (1:4)?

For 1:4 mortar (sum of parts s = 5): V_dry = 1 × 1.33 = 1.33 m³; cement volume = 1.33 / 5 = 0.266 m³; cement mass = 0.266 × 1440 = 383 kg; bags = ⌈383 / 50⌉ = 8 bags per m³ of wet mortar. Sand: 1.33 × 4/5 = 1.064 m³ = 1702 kg per m³ of wet mortar (before wastage). Always round bags up — partial bags are not available for purchase.

When should I use this tool vs the Brick Quantity Calculator?

Use the Brick Quantity Calculator (Tool 6) when you need brick count and mortar together for a wall defined by length × height × thickness. Use this Cement–Sand Calculator when you already know the wet mortar volume from a survey or measurement, or when calculating mortar for bedding/pointing/plastering without counting bricks. For example: repointing an existing wall (area known, no brick count needed), or ordering mortar for floor tile bedding or concrete block laying.

How is the wet mortar volume calculated from area and thickness?

V_wet (m³) = Net area (m²) × Bed thickness (m). For example, a 50 m² wall with 12 mm (0.012 m) mortar bed: V_wet = 50 × 0.012 = 0.6 m³. Then apply dry factor: V_dry = 0.6 × 1.33 = 0.798 m³. For Mode B (area × thickness) in this calculator, deductions for doors and windows can be entered to get the net area before calculating. Typical bed thickness: 10–12 mm for brickwork; 6–20 mm for plastering.

Does this calculator include plastering or pointing?

This is a general mortar-by-volume estimator. It works for any application where you know or can calculate wet mortar volume — including thin plaster coats if you set the area and thickness accordingly (e.g. Mode B with 6 mm or 12 mm thickness). It does not handle multi-coat plaster with different ratios per coat, texture paint, waterproofing, or pointing labour. A dedicated plaster estimator (Tool 9) is planned in the Speak Arch QS series.

Cement–Sand Mortar Calculator India

Order cement and sand for mortar by wet volume or area × bed thickness — mix 1:3 to 1:6, dry factor 1.33 (not 1.54).

Educational BOQ only. General mortar tool. For full brick wall BOQ use brick calculator. For plaster coats use plaster calculator.

How to use this calculator

Mode A: enter wet mortar m³, or Mode B: area × thickness.
Choose mix ratio and wastage.
Add opening deductions in Mode B.
Calculate bags and sand m³/kg.

Mix ratio (cement : sand)

Wastage

₹ / bag (optional cost)

OPC 43/53: ₹340–420/bag (50 kg) approximate 2025 rates.

Enter the total wet (placed) mortar volume you need. For brick wall BOQ including brick count, use the Brick Quantity Calculator.

Wet mortar volume *

Practical range: 0.05 m³ (small repair) to 10 m³ (large site order).

Wet volume —

Dry volume —

Cement vol —

Sand vol —

Cement (bags, rounded up)

—

Sand

—

Full breakdown

Item	Value	Unit

Constants & sources used

Mix ratio reference (IS 2212:2003)

Ratio	Cement %	Bags/m³ wet	Sand m³/m³ wet	Typical use
1:3	25%	10	0.998	External / severe exposure, waterproof masonry
1:4 ★	20%	8	1.064	General protected brickwork, most residential work
1:5	17%	7	1.108	Partition walls, non-load-bearing fillers
1:6	14%	6	1.140	Very lightly loaded non-structural fill

★ default · bags/m³ wet = ⌈(1.33/s × 1440/50)⌉ with 5% wastage. Values rounded for reference.

Frequently asked questions

Why 1.33 for mortar and not 1.54 like concrete?

Mortar (cement + sand) uses 1.33: V_dry = V_wet × 1.33. RCC concrete uses 1.54 because it includes coarse aggregate with larger air voids. Using 1.54 for mortar would overestimate cement and sand by ~16%. This calculator uses 1.33, consistent with CPWD analysis of rates, PLASTER_WORK.xlsx, and BRICK_WORK.xlsx verified sources.

Which ratio for brickwork mortar in India?

IS 2212:2003: 1:3 for severe/external exposure. 1:4 for general protected load-bearing brickwork (most residential — this is the default). 1:5 for partition walls. 1:6 for non-structural work. The ratio affects both cement bags and sand volume significantly — see the mix reference table below.

How many bags per m³ of mortar (1:4)?

V_dry = 1 × 1.33 = 1.33 m³; cement = 1.33/5 × 1440 = 383 kg = 8 bags (⌈7.66⌉). Sand: 1.33 × 4/5 = 1.064 m³ ≈ 1702 kg per m³ of wet mortar (no wastage). For 1:3: 10 bags/m³. For 1:6: 6 bags/m³. Always round bags up — partial bags are not sold.

Mode A vs Mode B — which should I use?

Mode A (direct volume): when you know the wet mortar volume from a survey, specification, or estimate. Mode B (area × thickness): when you have a wall or floor area and a bed thickness — the tool calculates V_wet = area × thickness. For full brick wall BOQ (brick count + mortar together), use the Brick Quantity Calculator instead.

Why is sand shown in both m³ and kg?

Indian BOQ and CPWD quote sand by volume (m³ or brass); site trucks are discussed in tonnes. This tool shows m³ primary (bulk density 1600 kg/m³ per CPWD), plus ft³ for sites using that unit. Source Excel files used cuft — this calculator converts to m³.

Does this include plastering or pointing?

Yes, indirectly. Use Mode B with area and your plaster thickness (e.g. 12 mm with 1:6 ratio for finish plaster). Multi-coat plaster with different ratios per coat is not handled — run separate calculations for each coat. A dedicated plaster estimator (Tool 9) is planned in the Speak Arch QS series.

Some references say use 1.60 as the dry factor — which is correct?

Both 1.33 and 1.60 appear in Indian QS literature. The 1.60 convention (used in PLASTER_QUANTITY.xlsx) accounts for 50% voids + 10% surface unevenness in one combined factor. The 1.33 convention (used in BRICK_WORK.xlsx, PLASTER_WORK.xlsx, and CPWD analysis of rates) is the more widely cited figure for standard site BOQ. The difference is about 20% on material quantities. This calculator uses 1.33 (consistent with verified CPWD-aligned source files). The constants panel documents both.