Reagent PPM Calculator
Reagent bottles are rarely 100% pure — that "98%" on the label matters when you need exactly 1,000 PPM. This calculator corrects for purity automatically.
Calculator
Reagent PPM Calculator
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Reagent bottles are rarely 100% pure — that "98%" on the label matters when you need exactly 1,000 PPM. This calculator corrects for purity automatically.
How to use this calculator
- Enter target PPM and volume.
- Enter reagent purity %.
- Get corrected grams.
The formula
Grams = PPM × L ÷ 1,000 ÷ (purity ÷ 100).
What the inputs mean
The target is the concentration you want, in PPM. The volume is how much liquid you are treating. The reagent purity (%) corrects for product strength, because most products are not 100% active ingredient. The result tells you exactly how much reagent to add.
Worked example
1 L at 1,000 PPM with 98% reagent: 1 ÷ 0.98 ≈ 1.02 g.
Quick reference
| Purity | Correction factor |
|---|---|
| 100% | 1.00 |
| 98% | 1.02 |
| 95% | 1.05 |
Multiply nominal grams by the factor.
Where you will actually use this
Purity correction is the difference between nominal and actual concentration.
- Analytical reagents
- Standard prep
- QC solutions
Mistakes that give wrong answers
- Ignoring purity
- Using expired reagents for standards
Key takeaways
- Formula: Reagent (g) = Target PPM × Volume (L) ÷ 1,000 ÷ purity
- Remember: Multiply nominal grams by the factor.
- Watch out for: Ignoring purity
- 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
Does reagent purity really matter?
At 95% purity you are 5% off — often outside analytical tolerance.