How many kg is one bag of cement?

The standard bag weight in most countries (including Nepal/India) is 50 kg.

How many bags of cement in 1 cubic metre of M20?

Approximately 8.2 bags of cement are used per cubic metre of M20 grade concrete.

Calculate for all structural members?

Get a full professional BOQ for slabs, beams, and columns → [Structural Master Estimator](/structural-master-estimator/)

How long should concrete be cured?

For standard RCC structures using OPC cement, continuous curing is required for at least 7 to 10 days. If using PPC or Fly-ash blended cement, a minimum of 14 days is recommended to ensure full structural strength and prevent shrinkage cracks.

What is the standard unit for sand in Nepal?

In Nepal, sand is typically sold by the cubic foot (CFT) or by the truckload (usually 100-300 CFT).

Does sand volume change when wet?

Yes, sand "bulks" (increases in volume) when it contains moisture. Always allow for a 10% volume variability in loosely piled wet sand.

Mix Ratio Cement Bags Sand Quantity Aggregate Quantity Dry Volume Concrete Density

Quality Inspector

Concrete & RCC

Concrete Raw Materials & Mix Estimator (Nepal Standards)

Expert Guide

Enter your total concrete volume and the specific mix ratio (Cement : Sand : Aggregate) to find the exact quantity of each material needed.

Concrete and RCC construction site with worker pouring concrete

⚡ Quick Answer

A concrete mix ratio (like 1:1.5:3 for M20) defines the volumetric proportions of Cement, Sand, and Coarse Aggregate. To find material quantities, multiply your wet concrete volume by 1.54 to find the total dry volume required before mixing.

🛠️ How It Works

The concrete mix ratio (C:S:A) determines the strength grade. Multiply the wet volume by 1.54 to get the dry volume, then divide by the sum of parts. Standard M20 (1:1.5:3) has a sum of 5.5 parts. Now calculate it here → Cement Bags Calculator

Enter the target wet volume of concrete you need to cast.
Select a standard Mix Grade (e.g., M20 for structural) or enter a custom ratio.
The engine automatically applies the 1.54 dry shrinkage factor.
It divides the total dry volume into individual components: Cement, Sand, and Aggregate.
Cement is converted from volume (m³) to standard 50kg bags using 0.0347 m³ per bag.

📐 Calculation Formula

Dry Volume = Wet Volume × 1.54

Cement (m³) = Dry Volume × (C / C+S+A)

Cement (Bags) = Cement (m³) / 0.0347

📋 Real-Life Example

For 10 m³ of M20 (1:1.5:3) concrete:
• Dry Volume = 10 × 1.54 = 15.4 m³
• Sum of parts = 5.5
• Cement Volume = 15.4 / 5.5 = 2.8 m³
• Cement Bags = 2.8 / 0.0347 = 81 bags

⚠️ Common Mistakes to Avoid

Assuming 1m³ of wet concrete requires 1m³ of dry ingredients. You actually need 1.54m³ of dry mix → Dry Volume Calculator
Using a weak M15 mix for critical members like columns or suspended slabs.
Not adjusting for moisture in the sand (bulking), which can affect the final volume and strength.
Adding too much water, which reduces the compressive strength of the concrete significantly.

❓ Frequently Asked Questions

What is the sum of parts in a mix ratio?

It is the total of all proportion values. For M20 (1:1.5:3), the sum is 1 + 1.5 + 3 = 5.5. For M15 (1:2:4), the sum is 7.

Why is the dry volume factor 1.54?

When sand, aggregate, and cement are dry, they have air voids. When water is added, these gaps are filled, causing the total volume to shrink by approx 35%. 1.54 is the standard factor to compensate for this.

Which ratio is recommended for earthquake-resistant columns?

In Nepal, M25 (1:1:2) or higher is often recommended for columns, while M20 (1:1.5:3) is the standard for slabs.

How much sand is in a 50kg bag of cement?

If using a 1:2:4 mix, one 50kg bag (approx 1.25 cu ft) would require 2.5 cu ft of sand and 5 cu ft of aggregate.