TryBuildCalcMortar Calculator (Cement & Sand for Masonry)
Estimate mortar cement and sand instantly.
🕒 Last updated: August 23, 2026
Inputs
ℹ️Typical: 115 mm (half brick), 230 mm (full brick)
Cost
For 0.85 m³ of masonry, you need approximately 2 cement bags and 0.23 m³ of sand.
Mortar Volume
Masonry volume: 0.855 m³
Wet mortar volume (~23% of masonry): 0.197 m³
Dry volume (×1.33): 0.261 m³
Materials
Cement: 1.3 bags — buy 2 bags
Sand: 0.229 m³ (~0.37 metric tons)
Sand tonnage is approximate, using 1.6 tons/m³ average bulk density.
Order Summary — Theoretical vs. Order Quantity
| Material | Theoretical | Order Quantity |
|---|---|---|
| Cement | 1.3 bags | 2 bags (whole) |
| Sand | 0.218 m³ | 0.229 m³ |
Theoretical = before wastage. Order Quantity = after your 5.0% wastage allowance (cement rounded up to a whole bag).
Assumptions Used
Mortar volume: ~23% of masonry volume | Dry volume factor: 1.33 | Cement bag: 50 kg / 0.0347 m³ | Wastage applied once to cement bags and sand volume.
Need brick or block counts with door/window opening deductions? Wall / Masonry Calculator →
Plastering this wall after masonry work? Cement Plaster Calculator →
Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete Mortar Calculator.
General mortar quantity estimate
This page gives the full combined mortar result — masonry volume, wet and dry mortar volume, cement bags, and sand — from one set of wall length, height, thickness, and mix ratio inputs.
It's the same calculator behind every other mortar variant on this site, just without a specific scenario pre-selected — useful for a general mortar estimate before finalizing the exact wall with your site engineer.
- Dry volume correction (×1.33) is applied before splitting into cement and sand.
- Supports four common cement:sand ratios from 1:3 (rich) to 1:6 (light).
- An optional per-material cost estimate can be turned on from the same form.
Mortar Formula: How Is Cement and Sand Quantity Calculated?
Mortar quantity is estimated as a percentage of total masonry volume, then converted into dry volume and distributed according to the cement:sand mix ratio.
Step 1 — Masonry & Mortar Volume
Masonry Volume = Wall Length × Wall Height × Wall Thickness
Wet Mortar Volume ≈ Masonry Volume × 0.23
Masonry volume is the total volume of brickwork including bricks and mortar joints. In standard brick masonry, mortar joints occupy approximately 20% to 25% of total masonry volume — commonly approximated as 23% in estimation practice.
Step 2 — Dry Volume Correction
Dry Volume = Wet Mortar Volume × 1.33
The dry volume factor accounts for sand bulking, voids between materials, and practical construction losses during mixing and application. Mortar uses 1.33 rather than concrete's 1.54 because it contains no coarse aggregate.
Step 3 — Mix Ratio Distribution
Cement Volume = Dry Volume × (Cement Part ÷ Total Parts)
Sand Volume = Dry Volume × (Sand Part ÷ Total Parts)
Dry mortar volume is divided according to the selected cement:sand mix ratio — 1:3 (rich, structural), 1:4 (strong brickwork), 1:5 (standard brickwork), or 1:6 (light masonry). Total Parts is the sum of both ratio parts.
Step 4 — Cement Bags Conversion
Cement Bags = Cement Volume ÷ 0.0347 m³/bag (50 kg bags)
One standard cement bag (50 kg) occupies approximately 0.0347 cubic metres. This conversion translates calculated cement volume into practical material procurement quantities.
Step 5 — Final Quantity with Wastage
Final Cement Bags = Cement Bags × (1 + Wastage %), rounded up to a whole bag
Final Sand Volume = Sand Volume × (1 + Wastage %)
Wastage is applied to both cement bags and sand volume for the practical order quantity — shown separately from the theoretical pre-wastage figures in the result card.
Worked Example
This example walks through your current inputs above, using the same steps as the Formula section.
Input Values Used
| Input | Value | Why it is used |
|---|---|---|
| Length × height × thickness | 10ft × 8ft × 115mm | Sets the total masonry volume |
| Mix ratio / wastage | 1:5, 5% wastage | Splits dry mortar volume into cement/sand and adds a buffer for site losses |
Step 1 — Masonry & Mortar Volume
| Calculation | Substitution | Result |
|---|---|---|
| Masonry volume | 10ft × 8ft × 115mm | 0.855 m³ |
| Wet mortar volume | 0.855 × 0.23 | 0.197 m³ |
| Dry volume | 0.197 × 1.33 | 0.261 m³ |
Step 2 — Cement & Sand
| Material | Theoretical | Order Quantity |
|---|---|---|
| Cement | 1.3 bags | 2 bags (whole) |
| Sand | 0.218 m³ | 0.229 m³ |
Therefore, for 0.85 m³ of masonry at a 1:5 mix, you need approximately 2 cement bags and 0.23 m³ of sand.
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Disclaimer: This calculator provides approximate results for planning and estimation purposes only. Actual requirements may vary based on site conditions, materials, workmanship, and local building regulations. Always consult a qualified engineer, architect, or construction professional before making final decisions.