Concrete Admixture Dosage Calculator
Professional concrete admixture calculator. Compute total admixture dosage by percent of cement, per 100 kg/lb, or per unit volume. Supports Metric and US customary units with an accessible, mobile-first interface.
Mix Inputs
Tip: Provide density to convert between mass and volume precisely.
How to Use This Calculator
This professional-grade concrete admixture calculator helps contractors, ready-mix producers, site engineers, and QC technicians compute total admixture requirements. Use it to determine dosage by percent of cement (bwoc), per 100 kg/lb of cement, or for a fixed volume amount. The interface automatically adapts labels for Metric and US customary systems, and results are expressed both by weight and volume when density is provided.
Enter the intended concrete volume and cementitious content, pick the dosage strategy, then supply the method-specific value and optional admixture density. Tap Calculate or rely on the debounced live updates to see how your choices impact mass, volume, and a concise summary.
Methodology
All figures are derived from standard mass and volume relationships used in concrete mix design. The calculator follows the guidance from ACI 212.3R-16 and ASTM C494/C494M to convert between cementitious mass, admixture percentage, and volume. Trailing decimals are rounded using consistent rules so the results remain deterministic across browsers.
- Percent of cement (bwoc) multiplies the total cementitious mass and optionally converts to volume when density is set.
- Per-100 kg/lb dosages scale linearly with cement mass and convert from milliliters (or fluid ounces) to volume.
- Per-unit-volume dosages multiply directly by the concrete volume that you enter.
Glossary of Inputs and Results
- Concrete volume — Total placed volume to be batched (m³ or yd³).
- Cementitious content per unit volume — Mass of cement plus SCMs per m³ or yd³ (kg/m³ or lb/yd³).
- Admixture density — Product density for mass/volume conversion (kg/L or lb/gal).
- % of cement (bwoc) — Dosage as a percentage of the cementitious mass.
- Per 100 kg/lb — Manufacturer-specified dose per 100 kg (or 100 lb) of cement.
- Per unit volume — Fixed admixture amount per m³ or yd³ of concrete.
- Total cementitious mass — Computed total cement/binder mass for the selected volume.
- Admixture mass — Total mass of admixture required in kg or lb.
- Admixture volume — Total volume of admixture required in liters or fluid ounces.
How It Works: A Step-by-Step Example
Suppose a slab pour of \(V=8\ \text{m}^3\) with cementitious content \(C=350\ \text{kg/m}^3\). A water-reducing admixture is specified at \(p=1.0\%\) bwoc, and density \(\rho=1.05\ \text{kg/L}\).
- Total cementitious mass: \(M_c = 8 \times 350 = 2{,}800\ \text{kg}\).
- Admixture mass: \(M_a = 0.01 \times 2{,}800 = 28\ \text{kg}\).
- Admixture volume: \(V_a = \frac{28}{1.05} \approx 26.67\ \text{L}\).
In practice, round to your plant’s batching resolution and stay within datasheet ranges from ACI 212.3R and ASTM C494.
Frequently Asked Questions
What is “bwoc”?
“By weight of cement” indicates dosage expressed as a percentage of the cementitious mass in the mix.
Should SCMs be included in cementitious content?
Yes. If the admixture dosage is specified relative to total binder, include SCMs (e.g., fly ash, slag, silica fume) in the cementitious content.
How do I select the right method?
Use “% of cement” when dosage is provided as a percentage by mass, “per 100 kg/lb” when the datasheet gives mL/100 kg or fl oz/100 lb, and “per unit volume” for fixed L/m³ or fl oz/yd³ directions.
What if I don’t know density?
You can still compute mass (percent method) or volume (per-100/per-volume methods). Provide density only when you need mass/volume conversions.
Are the results batch-ready?
They are theoretical totals. Always apply your plant’s calibration, batching tolerances, and quality procedures.
Can I mix unit systems?
No. Select one unit system (Metric or US). The tool adapts labels and calculations consistently.
What ranges are typical for water reducers?
Common ranges are roughly 0.2–1.0% bwoc, but consult the product datasheet and applicable standards.
Editorial policy
CalcDomain content is created for educational purposes and reviewed for clarity, accuracy, and transparency. We do not accept paid placements that influence outputs. Inputs and assumptions are shown directly in the interface so you can verify how results are produced.