Free Online Calculators
Calculate cement, sand, gravel & water
Planning a concrete project and wondering how much material you need? Our free concrete calculator takes the guesswork out of mixing concrete. Whether you're pouring a driveway, laying a foundation, or building a garden wall, enter your dimensions and instantly get the exact amounts of cement, sand, gravel, and water required – no manual calculations needed.
The calculator determines the quantities of all four core ingredients of standard concrete based on your project dimensions:
The tool uses the standard concrete mix ratio of 1:1.5:3 (cement:sand:gravel), which corresponds to a C20/25 concrete grade – the most commonly used ratio for residential and light commercial construction. This ratio balances workability, strength, and cost-efficiency perfectly for most DIY and professional projects alike.
Using the calculator is straightforward. Simply enter the three key dimensions of your concrete element:
The calculator first determines the required volume in cubic meters (or cubic feet), then automatically calculates the individual material quantities. You'll receive the weight of cement in kilograms, volumes of sand and gravel in cubic meters or tonnes, and water in liters. This makes your shopping list precise and your project planning effortless.
Suppose you need to pour a garage floor measuring 6 m × 4 m with a thickness of 15 cm. The volume is 6 × 4 × 0.15 = 3.6 m³. The concrete calculator instantly tells you that you'll need approximately 1,080 kg of cement, 1,620 kg of sand, 3,240 kg of gravel, and around 540 liters of water. Armed with this data, you can order the right quantities and avoid costly over-ordering or running short mid-pour.
A garden path 10 m long, 1 m wide, and 10 cm deep requires just 1.0 m³ of concrete. The calculator shows you whether a small portable mixer will suffice or whether you should consider ordering ready-mix concrete from a local supplier – saving you both time and physical effort.
Many DIY enthusiasts and even experienced builders tend to estimate concrete quantities by eye. This leads to two common and costly mistakes: ordering too little, which causes project delays and expensive re-orders, or buying too much, which wastes money and creates disposal problems for leftover concrete.
Beyond cost, the mix ratio directly affects concrete quality. Too much water weakens the structure and causes cracking. Too little cement reduces compressive strength. Getting the balance right is critical for a durable, weather-resistant result that will last for decades.
This tool is suitable for a wide range of projects in home improvement, landscaping, and construction:
Accurate quantities are the foundation of good concrete work, but mixing technique matters too:
The calculator uses the standard 1:1.5:3 mix ratio (cement:sand:gravel), which produces C20/25 grade concrete. This is suitable for most general construction purposes including slabs, foundations, and pathways. Specialist applications such as reinforced structural beams may require different ratios.
Yes. When you combine the dry ingredients with water, the total volume reduces by approximately 25–35% due to the particles filling the voids between each other. The calculator automatically compensates for this shrinkage to give you an accurate final concrete volume.
For standard C20/25 concrete, you need approximately 300 kg of cement per cubic meter. With standard 25 kg bags, that's about 12 bags per m³. The calculator gives you the exact figure for your specific project volume.
Absolutely. The total volume in cubic meters shown by the calculator is the standard unit used when ordering ready-mix or transit-mix concrete. Simply provide this figure to your supplier along with the required concrete grade.
The calculator provides material quantities for plain concrete. For reinforced concrete (with steel rebar), the concrete volume calculation remains valid, but you will need to separately account for the volume of steel reinforcement and potentially use a higher-strength mix design.