SettingsSettings for this calculationUS
The total cement plus any SCM, as mass per unit volume of concrete.
This is the mix design's binder content — see the Concrete Mix Ratio Calculator.
The desired water-to-cementitious ratio by mass.
Lower ratios (0.35-0.45) give higher strength and durability; higher ratios (0.55-0.65) improve workability but reduce strength and durability.
Water content required
9.832 pcf
- Equivalent water volume
- 31.81 gal/yd³
They open the calculator with your figures already in it
ACI 211.1 Water-Cement Ratio Calculator: 9.83 pcf — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- ACI 211.1 mix design procedure: water mass = target water-cement ratio x total cementitious material mass
Inputs used
- Total Cementitious Content
- 589.94 lb/yd³
- Target Water-Cement Ratio
- 0.45
Intermediate steps
- Equivalent water volume
- 31.81 gal/yd³
What this calculation does not cover
- This gives total design water, not batch water. It does not subtract the free moisture already riding on wet sand and coarse aggregate, and it does not add back the water that dry aggregate will absorb before it reaches saturated surface-dry. The water actually metered at the plant is this figure corrected for both.
- Nothing here checks the ratio you type against a durability limit. It multiplies your target by your binder content and stops; it does not test that target against the maximum water-cementitious ratio, minimum binder content, minimum strength or air content that an exposure condition imposes - freeze-thaw, deicing salts, sulfate soils or chloride exposure. A ratio your specification forbids is used exactly as entered.
- No strength or workability is predicted. Compressive strength and slump at a given water-cement ratio depend on cement type, which SCM is used and at what replacement, aggregate grading and particle shape, admixtures, curing and test age - none of which are inputs to this calculation.
- This is one arithmetic step, not a mix design. Coarse and fine aggregate quantities, air content, admixture dosage and the yield check that confirms the batch actually makes the volume it claims are all outside it.
- Water carried in liquid admixtures is not counted. Water reducers, superplasticisers and air-entraining agents dosed by volume contribute free water toward the ratio and are not deducted from the figure shown. The calculation also treats every unit of cementitious material as equally effective - where a specification applies an efficiency factor to fly ash or silica fume before it counts toward the denominator, that factor is not applied here.
Add the equipment this sizes
This result is a specification — 9.832 pcf — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-05 · in the site-wide review of 2026-09-06 · v1.1.2
Regulatory standards & verification citations1
- ACI 211.1 mix design procedure: water mass = target water-cement ratio x total cementitious material mass
Which documents these citations point at
Standards referenced: ACI 211.1 (American Concrete Institute, United States).
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