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Concrete Mix Ratio Calculator

Break a cement:sand:gravel mix ratio (like 1:2:3) into the actual volumes and cement bags needed for hand-mixed concrete.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-27 · v1.1.0

Market
Imperial · sales tax

Cement bags needed

5 x 94 lb cement bags

Check your inputs

This estimates raw material proportions for hand-mixing — actual yield is somewhat less than the sum of dry ingredient volumes since they pack together when mixed with water. For structural work, verify your mix design meets the required strength for its application.

Sand needed
9 ft³
Gravel needed
13.5 ft³

With the figures above, the cement bags needed comes to 5 x 94 lb cement bags. Note that cement parts sits at the low end of the range this calculator was checked against, so treat the output as indicative rather than settled. The method behind this is well established, though site conditions and material batches will move it somewhat. This is calculated for United States and cites IRC 2024. Building in another market? Change the selector above so the units and code reference follow.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Each component's volume = total volume x (its ratio parts / total ratio parts); a 94 lb bag of portland cement is commonly estimated at about 1 cubic ft loose volume

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Why hand-mix instead of using ready-mix concrete?
Hand-mixing from raw cement, sand, and gravel is mainly practical for small jobs where a ready-mix truck's minimum order doesn't make sense — for anything beyond a few cubic yards, ready-mix delivery (see the Concrete Calculator) is usually more practical and consistent.
What does the mix ratio actually control?
The proportion of cement (the binder) to aggregate (sand and gravel, the bulk filler) controls strength and workability — more cement generally means stronger but more expensive and harder-to-work concrete.
Is 1:2:3 the only ratio used?
No — it's a common general-purpose ratio, but structural applications sometimes use richer mixes (like 1:1.5:3) for higher strength, and non-structural fill or bedding can use leaner mixes. Check the requirements for your specific application.