TryBuildCalcM20 Mix Design Calculator(1:1.5:3 Nominal Mix)
Calculate cement bags, sand, aggregate, water, and optional material cost for concrete using common nominal mix ratios or grade presets.
Estimate concrete materials by ratio or grade.
🕒 Last updated: August 14, 2026
Inputs
Material Settings
ℹ️Default 1.54 for concrete material estimation.
ℹ️Typical range: 0.45 to 0.50 for nominal concrete estimation. Lower values may need better compaction or admixture.
Cost Settings
Theoretical Materials
8.06 bags
Cement Weight: 403.2 kg
Cement Volume: 0.28 m³
Sand: 0.42 m³ (14.83 ft³)
Aggregate: 0.84 m³ (29.66 ft³)
Water: 201.6 liters
Wet Volume: 1 m³ (35.31 ft³)
Dry Volume: 1.54 m³ (54.38 ft³)
Ratio Used: 1:1.5:3
Grade Preset: M20
Recommended Materials
(Including 5% Wastage)
8.47 bags
Cement: 423.36 kg (0.294 m³)
Sand: 0.441 m³ (15.57 ft³)
Aggregate: 0.882 m³ (31.15 ft³)
Water: 211.7 liters
Water-Cement Ratio: 0.5
M20 nominal mix quantity estimate
This page is pre-selected to M20 (1:1.5:3) — the richest of the standard Indian nominal mixes and the minimum grade IS 456 permits for reinforced concrete work.
Edit the concrete volume above and the cement bags, sand, aggregate, and water breakdown update from your active inputs, using the same 1:1.5:3 ratio.
- M20 (1:1.5:3) is commonly used for RCC slabs, beams, columns, and footings in nominal-mix practice.
- M20 is the highest grade generally permitted as a nominal (prescriptive) mix — M25 and above require a lab-verified design mix under most codes.
- Roughly 8 cement bags are typically needed per cubic metre for M20, before wastage.
Concrete mix calculation formula
Concrete mix quantity calculation starts with the required wet concrete volume, then converts it into dry material volume. The dry volume is divided between cement, sand, and aggregate according to the selected mix ratio.
Step 1 - Wet Concrete Volume
The wet concrete volume is the final concrete volume required at site. In this calculator, the user enters this value directly in m³ or ft³.
Step 2 - Dry Volume
Dry volume accounts for voids between aggregates, bulking, compaction, and handling losses. For nominal concrete estimation, 1.54 is commonly used.
Step 3 - Total Mix Parts
The selected concrete ratio is split into cement, sand, and coarse aggregate parts. For example, 1:2:4 has 7 total parts.
Step 4 - Cement, Sand, and Aggregate Volume
Each material receives its share of the dry volume based on the selected ratio.
Cement Volume = Cement Part / Total Parts x Dry Volume
Sand Volume = Sand Part / Total Parts x Dry Volume
Aggregate Volume = Aggregate Part / Total Parts x Dry Volume
Step 5 - Cement Weight and Cement Bags
Cement volume is converted into weight using a standard cement density of 1440 kg/m³. The number of bags is then calculated using the selected cement bag weight.
Cement Weight = Cement Volume x 1440
Cement Bags = Cement Weight / Cement Bag Weight
Step 6 - Water Requirement
Water is estimated from cement weight and the selected water-cement ratio. Since 1 kg of water is approximately 1 liter, the water quantity is shown in liters.
Step 7 - Wastage Allowance
Wastage allowance is applied to the calculated material quantities to cover handling losses, small batching differences, spillage, and practical site variation.
Example concrete mix calculation
This example uses the active calculator inputs above and follows the same steps from the formula section — showing the default scenario if you haven't changed anything, or your own live inputs once you do.
Input Values Used
| Input | Value | Why it is used |
|---|---|---|
| Concrete volume | 1.00 m³ | Sets the total wet concrete volume to estimate |
| Mix ratio | 1:1.5:3 (Grade M20) | Splits dry volume into cement, sand, and aggregate parts |
| Dry volume factor | 1.54 | Converts wet volume to dry material volume |
| Cement bag weight | 50 kg | Converts cement weight into bag count |
| Water-cement ratio | 0.50 | Sets water quantity from cement weight |
| Wastage allowance | 5% | Adds a buffer for handling and site losses |
Step 1 — Dry Volume
| Calculation | Substitution | Result |
|---|---|---|
| Dry Volume | 1.00 × 1.54 | 1.54 m³ |
Step 2 — Total Mix Parts
| Calculation | Substitution | Result |
|---|---|---|
| Total Parts | 1 + 1.5 + 3 | 5.5 |
Step 3 — Cement Volume, Weight & Bags
| Calculation | Substitution | Result |
|---|---|---|
| Cement Volume | 1 / 5.5 × 1.54 | 0.28 m³ |
| Cement Weight | 0.28 × 1440 | 403.20 kg |
| Cement Bags | 403.20 / 50 | 8.06 bags |
Step 4 — Sand & Aggregate Volume
| Calculation | Substitution | Result |
|---|---|---|
| Sand Volume | 1.5 / 5.5 × 1.54 | 0.42 m³ |
| Aggregate Volume | 3 / 5.5 × 1.54 | 0.84 m³ |
Step 5 — Water Requirement
| Calculation | Substitution | Result |
|---|---|---|
| Water | 403.20 × 0.50 | 201.6 liters |
Step 6 — With 5% Wastage
| Calculation | Substitution | Result |
|---|---|---|
| Cement Bags | 8.06 × (1 + 5 ÷ 100) | 8.47 bags |
| Sand | 0.42 × (1 + 5 ÷ 100) | 0.44 m³ |
| Aggregate | 0.84 × (1 + 5 ÷ 100) | 0.88 m³ |
| Water | 201.6 × (1 + 5 ÷ 100) | 211.7 liters |
Therefore, for 1.00 m³ of concrete using a 1:1.5:3 mix, you need 8.47 cement bags, 0.44 m³ of sand, and 0.88 m³ of aggregate.
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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.