Calculator Inputs
Example Data Table
Illustrative results for common cement–lime mortar mixes. Adjust to your site specification and codes.
| Mix Ratio (C:L:S) | Target Wet Volume | Dry Factor | Waste | Outputs (Approx.) |
|---|---|---|---|---|
| 1 : 1 : 6 | 0.50 m³ | 1.33 | 5% | Cement 0.10 m³, Lime 0.10 m³, Sand 0.60 m³ |
| 1 : 0.5 : 4.5 | 1.00 m³ | 1.33 | 5% | Cement 0.26 m³, Lime 0.13 m³, Sand 1.17 m³ |
| 1 : 1 : 5 | 35.0 ft³ | 1.33 | 8% | Quantities split by parts; convert to mass using densities |
The calculator computes volumes and masses, then estimates bag counts from selected bag sizes.
Formula Used
- Unit conversion: 1 m³ = 35.3146667 ft³.
- Dry volume: DryVolume = WetVolume × DryFactor.
- Waste adjustment: DryAdj = DryVolume × (1 + Waste% ÷ 100).
- Parts total: TotalParts = C + L + S.
- Component volume: Vx = DryAdj × (Partsx ÷ TotalParts).
- Component mass: Mx = Vx × Densityx (kg/m³).
- Bag count: Bags = Mx ÷ BagSize (kg).
- Water estimate (optional): Water ≈ (CementMass + LimeMass) × (w/b).
Density and water demand vary by material source, moisture, and grading. For specifications, follow your project requirements and local standards.
How to Use This Calculator
- Enter the target mortar volume you need (wet volume).
- Select your mix ratio as cement:lime:sand parts.
- Keep the dry volume factor near 1.33 unless specified otherwise.
- Add a wastage percentage based on handling conditions.
- Adjust material densities and bag sizes to match supplier data.
- Optionally enable water estimate and set a water-to-binder ratio.
- Press Calculate to see results above the form.
- Use Download CSV or Download PDF after calculating.
For best accuracy, measure sand moisture and correct batching weights accordingly.
Professional Article: Mortar Lime Ratios for Consistent Masonry Work
Mortar quality depends on proportioning, batching discipline, and site conditions. Lime is commonly introduced to improve workability, water retention, and board life, especially in hot or windy environments. A mortar “ratio” expresses the relative parts of cement, lime, and sand by volume. When you scale a mix to a target mortar volume, the calculator first converts the wet requirement into an equivalent dry volume using a dry factor, then allocates that dry volume across the chosen parts. This approach keeps the mix balanced even when the project requires small or large batches.
Start by selecting a ratio that matches the application. A richer binder content (more cement and/or lime relative to sand) increases cohesiveness and early strength, while leaner mixes can reduce shrinkage and cost but may be less adhesive. Lime can also reduce cracking tendencies by improving plasticity, but excessive lime may lower early strength and increase setting time. Sand grading matters: well-graded, clean sand typically produces better packing and reduced voids, which can lower binder demand.
The calculator reports both volumes and masses. Volumes help with on-site gauge boxes, while masses help when you purchase by bag. Densities differ by supplier and moisture condition, so treat defaults as starting points and adjust them with product data sheets. Add a realistic waste percentage for spillage, handling, and leftover mortar at the end of the shift.
Example: Suppose you need 0.50 m³ of finished mortar with a 1:1:6 (cement:lime:sand) ratio, dry factor 1.33, and waste 5%. The adjusted dry volume becomes approximately 0.50 × 1.33 × 1.05 ≈ 0.698 m³. Total parts are 8, so each part is about 0.087 m³. Cement and lime are ~0.087 m³ each, and sand is ~0.523 m³. Using typical densities, cement is roughly 125 kg (about 2.5 bags of 50 kg) and lime is roughly 39 kg (about 1.6 bags of 25 kg).
Finally, confirm the result against your project specification and local practice. Trial a small batch, observe workability and finish, then fine-tune the ratio, water, or sand grading before committing to high-volume production. Consistency beats perfection on most sites, so measure the same way every time.
FAQs
1) What does a 1:1:6 ratio mean?
It means 1 part cement, 1 part lime, and 6 parts sand by volume. The calculator scales these parts to your required mortar volume and waste allowance.
2) Why is a dry volume factor used?
Dry ingredients occupy more volume than finished mortar because voids collapse during mixing. The dry factor approximates that conversion so material quantities are not underestimated.
3) Can I set lime parts to zero?
Yes. If you use a cement–sand mortar, set lime parts to 0 and keep cement and sand parts positive. The calculator will allocate dry volume accordingly.
4) How accurate are the bag estimates?
Bag counts depend on the bulk density you enter and the bag size selected. Use supplier data whenever possible, and round up to cover handling losses and partial bags.
5) Should I change sand density for wet sand?
Moisture affects both density and batching by volume. If your sand is very wet, adjust density upward and consider moisture corrections to prevent overly wet mortar.
6) What water-to-binder ratio should I use?
Use the optional water estimate only as a starting point. Typical ranges vary widely by sand grading and lime content, so trial batches and finish requirements should guide final water addition.
7) Does this replace project specifications?
No. It supports planning and purchasing, but your drawings, specifications, and local standards control the final mix. Always verify ratios and materials with your project engineer or supervisor.