# How much concrete material do I need per cubic meter: how to calculate it A 5×4 m slab, 10 cm thick, needs 2 m³ of concrete. How to calculate volume and where to check the exact mix proportion. By the Grupo Server editorial team · [Editorial policy](https://gruposerver.com.mx/en/blog/editorial/) Published September 2, 2026 · Updated September 9, 2026 To know how much concrete you need, first calculate the element's volume —length by width by thickness, in meters— and then add a waste allowance. A 5 by 4 meter slab, 10 centimeters thick, needs 5 × 4 × 0.10 = 2 cubic meters of concrete. The exact proportion of cement, sand, gravel and water depends on the design f'c and should be checked in the cement manufacturer's table, under NMX-C-414-ONNCCE-2017. **Key facts** - A slab or floor topping's volume is calculated as length × width × thickness, all in meters. - f'c is concrete's specified 28-day compressive strength, in kg/cm². - NMX-C-414-ONNCCE-2017 has governed hydraulic cementitious material specifications since January 2018. - Aggregates —sand and gravel— are 60–70% of concrete's volume, per GCC (August 2020). - The exact mix proportion depends on the f'c, the maximum aggregate size and the cement used. ## What does f'c mean and why does it determine the mix? f'c is concrete's specified compressive strength, measured in kilograms per square centimeter (kg/cm²) or megapascals (MPa), which the mix must reach 28 days after pouring. It is the central figure of any structural project: floor toppings, slabs, foundations and load-bearing elements each carry a different design f'c, set by the project's structural calculations, not by site custom. That f'c value is what determines the proportion of cement, sand, gravel and water in the mix. A higher required f'c usually means a higher proportion of cement relative to aggregate, but the exact ratio is not a fixed site rule: it is set by the mix design from the cement manufacturer or the ready-mix concrete supplier, checking that the cementitious material meets [NMX-C-414-ONNCCE-2017](https://dof.gob.mx/nota_detalle.php?codigo=5510053&fecha=04/01/2018). ## How do you calculate the concrete volume for a slab or floor topping? The volume of a rectangular concrete element —slab, floor topping or footing— is calculated by multiplying its three dimensions, all in meters: length × width × thickness. The result is the volume in cubic meters (m³), the unit in which ready-mix concrete is purchased or site-batched concrete is measured. For example, an 8-meter by 6-meter floor topping, 10 centimeters thick — that is, 0.10 meters — needs: 8 m × 6 m × 0.10 m = 4.8 cubic meters of concrete. | Element (example) | Dimensions | Volume | | --- | --- | --- | | Slab | 5 m × 4 m × 0.10 m | 2.0 m³ | | Floor topping | 8 m × 6 m × 0.10 m | 4.8 m³ | | Strip footing | 10 m × 0.60 m × 0.30 m | 1.8 m³ | All three are geometric examples, with no waste allowance added. If the element is not rectangular, split it into rectangular or triangular sections, calculate each one's volume separately, and add them up. This is a pure geometry calculation: it does not depend on the f'c or the mix design, only on the element's actual dimensions. The same calculation applies to a foundation or a footing, even though its shape is more irregular than a slab: break the element down into simple volumes — mostly rectangular prisms — and add each one separately. The final result, in cubic meters, is the figure shared with the ready-mix concrete supplier, or the one used to calculate how much cement, sand and gravel to buy if the mix is batched on site. ## What is waste allowance and why does it need to be added? Waste allowance is the extra material added on top of the geometric volume, to cover losses that happen in practice: concrete left in the mixer or the pump, ground or formwork irregularities that make the real element use more material than the drawing shows, and losses in handling during the pour. The waste percentage is not a single or standardized figure: it varies with the pouring method, the condition of the formwork, the crew's experience and site conditions. It is best worked out with the site foreman or the concrete supplier for each project, rather than applying a generic figure. Ordering too little usually costs more than ordering a bit extra: if the calculated volume falls short, the pour stops midway, which can leave an unplanned cold joint in the element. For that reason, many ready-mix concrete suppliers ask for the volume to be confirmed with a margin before pour day, rather than adjusting the order on the spot. ## Where do you find the exact mix proportion? The exact proportion of cement, sand, gravel and water for a given f'c is not a universal figure: it depends on the cement brand and type, the maximum size of the available aggregate, and local water and aggregate conditions. That is why the right source is the mix-design table published by the cement manufacturer you plan to use, checking that the cementitious material meets NMX-C-414-ONNCCE-2017. Beyond that table, it is worth checking that the sand and gravel meet [NMX-C-111-ONNCCE-2018](https://dof.gob.mx/nota_detalle.php?codigo=5543504&fecha=12/11/2018), because a mix that is well designed on paper can still fail if the aggregate does not have the [grading or cleanliness the standard requires](https://gruposerver.com.mx/en/blog/que-es-un-agregado-petreo/). ## How does Grupo Server help? Triturados Gramol, a Grupo Server company founded in 2003, produces the sand and gravel combined with cement and water in concrete, with two operating plants in Coahuila and San Luis Potosí. Vermat, the group's distribution chain, [supplies cement and materials](https://gruposerver.com.mx/en/blog/como-elegir-una-tienda-de-materiales-en-saltillo/) to anyone batching their own mix on site. You can review [Triturados Gramol's profile](https://gruposerver.com.mx/en/empresas/triturados-gramol/), browse the group's [construction section](https://gruposerver.com.mx/en/construccion/), or write in through the [contact form](https://gruposerver.com.mx/en/contacto/) to work out an aggregate order for your project. ## Frequently asked questions ### What does f'c 200 or f'c 250 mean? f'c is concrete's specified compressive strength, expressed in kilograms per square centimeter, that the mix must reach at 28 days. f'c 200 and f'c 250 are two different design values, each with its own mix proportion. ### How do I calculate how many cubic meters of concrete a slab needs? Multiply the slab's length by its width by its thickness, all in meters. A 5 by 4 meter slab, 10 centimeters (0.10 m) thick, needs 5 × 4 × 0.10 = 2 cubic meters of concrete. ### What is waste allowance in a concrete calculation? It is the extra material added on top of the geometric volume, to cover losses in mixing, transport, pouring and irregularities in the formwork. The exact percentage is set project by project, based on its conditions. ### Where do I find the cement, sand, gravel and water proportion for a given f'c? In the mix-design table published by the cement manufacturer you plan to use, checking that the cementitious material meets NMX-C-414-ONNCCE-2017. ### Is the amount of sand and gravel per m³ of concrete always the same? No. It depends on the design f'c, the maximum aggregate size and the cement manufacturer's specific mix design; there is no single proportion valid for every case. ## Topics - Grupo Server - Triturados Gramol - Saltillo - Coahuila - NMX-C-414-ONNCCE-2017 ## Sources - [NMX-C-414-ONNCCE-2017, Diario Oficial de la Federación, January 4, 2018](https://dof.gob.mx/nota_detalle.php?codigo=5510053&fecha=04/01/2018) - [NMX-C-111-ONNCCE-2018, Diario Oficial de la Federación, November 12, 2018](https://dof.gob.mx/nota_detalle.php?codigo=5543504&fecha=12/11/2018) - [GCC, Aggregates technical data sheet (August 2020)](https://www.gcc.com/wp-content/uploads/2020/08/FT-0620-AGREGADOS-PÉTREOS.pdf) - Triturados Gramol company profile Spotted an incorrect fact? Tell us the article title through the [contact form](https://gruposerver.com.mx/en/contacto/). ## Keep exploring the site [Construction](https://gruposerver.com.mx/en/construccion/)[Group companies](https://gruposerver.com.mx/en/empresas/)[Contact](https://gruposerver.com.mx/en/contacto/) ## Related articles - MaterialsSeptember 2, 2026 ## [Types of sand for construction: river, manufactured, silica and volcanic](https://gruposerver.com.mx/en/blog/tipos-de-arena-para-construccion/) Aggregates —sand included— make up 60–70% of concrete's volume (GCC, 2020). A guide to the 4 sand types and how each is used. - MaterialsSeptember 2, 2026 ## [Types of gravel and their sizes: 3/8, 3/4, 1 and 1½ inches](https://gruposerver.com.mx/en/blog/tipos-de-grava-y-sus-tamanos/) GCC grades crushed gravel in 3/8, 3/4, 1 and 1½ inches (NMX-C-111-ONNCCE-2018). Sizes, uses and the difference with fine gravel. - MaterialsSeptember 2, 2026 ## [Concrete block: types, strength and how to read the data sheet](https://gruposerver.com.mx/en/blog/block-de-concreto-medidas-tipos-y-resistencia/) Concrete block in Mexico is regulated by NMX-C-404-ONNCCE-2012, in force since February 11, 2013. Types and what to require in the data sheet. - MaterialsSeptember 2, 2026 ## [What is a stone aggregate: definition, types and how it is made](https://gruposerver.com.mx/en/blog/que-es-un-agregado-petreo/) Stone aggregate —sand and gravel— is 60–70% of concrete's volume (GCC, 2020). What it is, its types, and how a quarry produces it. --- Fuente: https://gruposerver.com.mx/en/blog/cuanto-material-necesito-para-un-metro-cubico-de-concreto/ · Índice para agentes: https://gruposerver.com.mx/llms.txt · Sitemap: https://gruposerver.com.mx/sitemap.xml