🧱 Concrete Mix Ratio Calculator
Enter your mix ratio and the concrete volume you need to see the cement, sand, and aggregate quantities, with cement converted into bags using a dry-volume factor.
🧱 Estimate Your Mix Quantities
What is a Concrete Mix Ratio Calculator?
A concrete mix ratio calculator takes the proportions of cement, sand, and aggregate and the volume you want to pour, then tells you how much of each material to batch. It applies a dry-volume factor so the dry ingredients fill the form once mixed and compacted.
Set the ratio — for example 1:2:3 for general structural concrete — enter the wet volume, and read off cement bags plus sand and aggregate volumes. These are estimates for planning; verify with a structural engineer for load-bearing work.
❓ Frequently Asked Questions
What does a concrete mix ratio like 1:2:3 mean?
It is the proportion by volume of cement to sand to coarse aggregate. A 1:2:3 mix (often called M20) is one part cement, two parts sand, and three parts stone. A richer 1:1.5:3 gives higher strength for structural work, while a leaner 1:3:6 suits mass concrete and fill. The calculator splits your volume into those parts.
Why multiply by a 1.54 dry-volume factor?
Dry cement, sand, and aggregate have air voids that disappear once you add water and compact the mix, so the dry materials always exceed the finished wet volume. Multiplying the wet volume by about 1.54 accounts for that bulking and for compaction, so you batch enough dry material to fill the form.
How many bags of cement are in a cubic foot?
A standard bag of cement loosely fills roughly 1.25 cubic feet, so the calculator divides the required cement volume by 1.25 and rounds up to whole bags. Knowing the bag count up front makes it easy to price the job and order without trips back to the supplier.
Are these mix quantities exact?
They are estimates for planning; verify with a structural engineer for load-bearing work. Real mixes also depend on the water-cement ratio, aggregate moisture, and the strength class you need, which a proper mix design specifies. Use these figures to batch and order, then follow your design for the final proportions.