Concrete Mix Design Calculator
A concrete mix design calculator helps you determine the proportions of cement, water, fine aggregate, and coarse aggregate needed to produce concrete with a specific compressive strength and workability. Proper mix design is critical for structural performance, durability, and economy. Using too much water weakens the mix; too little makes it unworkable. The ACI 211.1 method, which this calculator follows, selects the water-cement ratio based on target strength, estimates water content from aggregate size and slump, then calculates aggregate and cement weights to fill a unit volume. Enter your target 28-day compressive strength, maximum aggregate size, and desired slump to get the ingredient quantities per cubic yard of concrete.
ACI 211.1 mix design method
w/c ratio: selected from ACI Table 6.3.4 based on target strength
Water content: from ACI Table 6.3.3 based on slump and max aggregate size
Cement = Water / (w/c ratio)
Coarse aggregate: from ACI Table 6.3.6 as fraction of dry-rodded unit weight
Fine aggregate: fills remaining volume
Yield check: sum of absolute volumes = 27 cubic feet (1 cubic yard)
This calculator uses simplified representative values from ACI 211.1. Actual mix designs require laboratory trial batches and testing to verify.
Frequently asked questions
What is concrete mix design?
Concrete mix design is the process of selecting the proportions of cement, water, fine aggregate (sand), and coarse aggregate (gravel or crushed stone) to achieve the required strength, workability, and durability. The goal is the most economical mix that meets project specifications.
What does water-cement ratio mean?
The water-cement (w/c) ratio is the weight of water divided by the weight of cement in a concrete mix. A lower w/c ratio produces stronger, less permeable concrete. ACI 318 specifies maximum w/c ratios based on exposure conditions, ranging from 0.40 for severe exposure to 0.60 for normal conditions.
What is a normal concrete mix ratio?
A common nominal mix ratio for general construction is 1:2:4 (cement:sand:aggregate by volume), which typically yields a compressive strength of around 3,000 psi. For higher strength, use 1:1.5:3, which can achieve 4,000 to 5,000 psi with a low water-cement ratio.
How much does one cubic yard of concrete weigh?
Normal weight concrete weighs approximately 3,900 to 4,050 pounds (about 145-150 lb per cubic foot) per cubic yard. This equates to roughly 1.75 to 1.85 metric tonnes per cubic metre.
What is slump in concrete?
Slump measures the workability (consistency) of fresh concrete. A higher slump means more fluid and workable concrete. Typical slumps range from 1 inch (stiff mixes for pavements) to 5 inches (pumpable mixes for walls and columns). Adding water increases slump but reduces strength.
Official sources
- American Concrete Institute: ACI 211.1 Standard Practice for Selecting Proportions for Normal, Heavyweight, and Mass Concrete.
- Portland Cement Association: Concrete Mix Design Guide.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.