Concrete Chloride PPM Checker
Chloride in concrete corrodes the steel inside it — and the limits are written in PPM by weight of cement: under 1,000 for reinforced, under 500 for prestressed. Convert your % reading and check.
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Concrete Chloride PPM Checker
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Chloride in concrete corrodes the steel inside it — and the limits are written in PPM by weight of cement: under 1,000 for reinforced, under 500 for prestressed. Convert your % reading and check.
How to use this calculator
- Enter chloride % (by cement weight).
- Convert to PPM.
- Compare with the structural limits.
The formula
% × 10,000 = PPM; limits per ACI 318.
What the units mean
Percent — parts per hundred. The everyday unit for concentrations large enough to read as a percentage.
PPM (parts per million) — one part of solute per million parts of the total mixture. The workhorse unit for trace concentrations in water, air, and food.
Worked example
0.08% chloride → 800 PPM — OK for reinforced, over for prestressed.
Quick reference
| Structure | Limit |
|---|---|
| Reinforced | <1,000 PPM |
| Prestressed | <500 PPM |
By weight of cement (ACI 318).
Where you will actually use this
Chloride-induced corrosion is the #1 cause of concrete structure decay.
- Structural assessment
- New construction QC
- Repair planning
Mistakes that give wrong answers
- % of concrete vs % of cement (different!)
- Ignoring chloride already in aggregates
Key takeaways
- Formula: PPM = chloride % × 10,000
- Remember: By weight of cement (ACI 318).
- Watch out for: % of concrete vs % of cement (different!)
- Next step: run your own numbers in the calculator above, then verify with a measurement — calculated values are only as good as the inputs.
Frequently asked questions
What is the chloride limit in concrete?
~1,000 PPM (reinforced), ~500 PPM (prestressed) by cement weight.