PPM Calculation Examples (10 Worked Problems) | Step-by-Step Solutions

If you’ve already learned the formula for PPM (Parts Per Million) but want to see it in action, this page walks through 10 real-world examples.
Each one uses slightly different data types—liquids, solids, gases, and industrial cases—so you can apply the right formula confidently.

1️⃣ Water Solution Example (mg/L)

Question: How many ppm are in a solution with 25 mg of salt dissolved in 5 L of water?
Formula:

PPM = (Mass of Solute / Volume of Solution) × 1,000,000

Calculation:
(25 mg ÷ 5 L) = 5 mg/L = 5 ppm

✅ Try verifying in the PPM Calculator.

2️⃣ Air Quality Example (Gas Concentration)

Question: An air sample contains 0.0005 L of CO₂ in 1 L of air. What’s the ppm?
Formula:

PPM = (Volume of Gas / Total Volume) × 10⁶

Calculation:
(0.0005 ÷ 1) × 1,000,000 = 500 ppm CO₂

For more environmental cases, see PPM Calculator for Environmental Testing.

3️⃣ Soil Contamination Example (µg/g)

Question: Soil contains 8 µg of lead per gram of sample.
Calculation:
PPM = (8 µg ÷ 1 g) = 8 ppm Pb

Confirm with the PPM to Mass Calculator.

4️⃣ Manufacturing Defects Example

Question: A factory found 6 defective parts out of 1,000,000 produced.
Formula:

PPM = (Defects / Total Units) × 10⁶

Calculation:
(6 ÷ 1,000,000) × 1,000,000 = 6 ppm defects

You can convert this to process capability using the PPM to Six Sigma Calculator.

5️⃣ Chlorine in Pool Water

Question: A 1 L pool sample shows 0.003 g (3 mg) of chlorine.
PPM = (3 mg ÷ 1 L) = 3 ppm chlorine
This level falls within the WHO-recommended safe range of 1–3 ppm.
Use the Pool Chlorine PPM Calculator to confirm.

6️⃣ Industrial Gas Purity Example

Question: A gas cylinder contains 0.001 % impurity. Convert to ppm.
Formula:

PPM = % × 10,000

Calculation:
0.001 % × 10,000 = 10 ppm impurities

See similar conversions in the PPM Conversion Table.

7️⃣ Laboratory Chemical Dilution

Question: How many ppm is 0.02 g of NaCl dissolved in 1 L water?
0.02 g × 1000 mg/g = 20 mg → 20 ppm
Check via How to Calculate PPM Step by Step.

8️⃣ Electronics Frequency Drift

Question: A 10 MHz oscillator has a tolerance of ±15 ppm.
Drift = (15 × 10,000,000) ÷ 1,000,000 = ±150 Hz
Use the Frequency PPM Calculator to model drift.

9️⃣ Nutrient Solution in Hydroponics

Question: Your fertilizer solution contains 1200 ppm total nutrients.
If a dilution halves concentration, new ppm = 1200 ÷ 2 = 600 ppm.
Check related conversions with the Nutrient PPM Calculator.

🔟 Heavy-Metal Analysis (mg/kg)

Question: A metal sample has 0.0005 g of cadmium in 250 g of alloy.
Convert to mg/kg:
0.0005 g = 0.5 mg; 250 g = 0.25 kg → (0.5 ÷ 0.25) = 2 ppm Cd

Tips for Verifying PPM Calculations

• Keep units consistent (mg ↔ L, µg ↔ g).
• Check formulas using PPM Formula Variations.
• Compare results against Global PPM Standards for Drinking Water or other relevant docs.
• If results seem off, see Troubleshooting PPM Calculator Results.

FAQs

Are ppm values always linear?
Yes, ppm expresses a linear ratio — doubling solute doubles ppm.

Can I add ppm values directly?
Only for identical substances under the same conditions.

Why do different calculators show slight variations?
Some assume water density (1 g/mL), others include temperature corrections.

Summary

• PPM uses the ratio solute ÷ solution × 1,000,000.
• Always verify the correct formula for your material type.
• Use online tools for conversions and double-checks.
• Keep records of all units and assumptions for reproducibility.