PPM Calculator
Convert parts per million to mg/L, percent, ppb, ppt, mg/kg and other concentration units, work out the ppm of a solution from the masses, or the amount of solute needed to reach a target ppm. For gases, convert ppm by volume to mg/m³ using the molar mass.
1 for water and dilute solutions; seawater ≈ 1.025
Adds mol/L and mmol/L
100% for a pure chemical; e.g. 6 for 6% bleach
Gives the product volume in mL
101.325 kPa = 1 atm
How to use the PPM Calculator
- Choose a mode: convert units, ppm of a solution, amount needed, or gas ppm ↔ mg/m³.
- Enter the value and choose its unit.
- Check the density (1 g/mL for water and dilute water solutions) when converting between mass and volume units.
- For gases, enter the formula (e.g. CO, NH3) or the molar mass, plus temperature and pressure.
- Read the result and the full conversion table, or copy it.
PPM formulas
- ppm by mass = mass of solute ÷ mass of solution × 1,000,000 (1 ppm = 1 mg/kg)
- ppm from mg/L = mg/L ÷ density (g/mL). For water, 1 mg/L ≈ 1 ppm.
- Percent = ppm ÷ 10,000; ppb = ppm × 1,000
- Solute needed = target ppm × solution mass ÷ 1,000,000 (divide by the product strength for a diluted product)
- Gases: mg/m³ = ppm × M ÷ Vm, with Vm = R T ÷ P = 24.47 L/mol at 25 °C and 1 atm
Concentration conversion table (water, density 1 g/mL)
| ppm | Percent | ppb | mg/L | g/L |
|---|---|---|---|---|
| 0.001 | 0.0000001% | 1 | 0.001 | 0.000001 |
| 1 | 0.0001% | 1,000 | 1 | 0.001 |
| 10 | 0.001% | 10,000 | 10 | 0.01 |
| 100 | 0.01% | 100,000 | 100 | 0.1 |
| 1,000 | 0.1% | 1,000,000 | 1,000 | 1 |
| 10,000 | 1% | 10,000,000 | 10,000 | 10 |
Gas ppm to mg/m³ at 25 °C and 1 atm
| Gas | Molar mass (g/mol) | 1 ppm equals |
|---|---|---|
| Carbon monoxide (CO) | 28.01 | 1.145 mg/m³ |
| Carbon dioxide (CO₂) | 44.01 | 1.799 mg/m³ |
| Ammonia (NH₃) | 17.03 | 0.696 mg/m³ |
| Nitrogen dioxide (NO₂) | 46.01 | 1.881 mg/m³ |
| Sulfur dioxide (SO₂) | 64.06 | 2.619 mg/m³ |
| Ozone (O₃) | 48.00 | 1.962 mg/m³ |
Frequently asked questions
What does ppm mean?
Parts per million: one part of a substance per million parts of the whole. By mass, 1 ppm = 1 mg per kg = 0.0001%. For gases, ppm usually means parts per million by volume (ppmv), i.e. 1 mL of gas per cubic metre of air.
Is 1 ppm equal to 1 mg/L?
For water and dilute water solutions, yes, approximately: one litre of water has a mass of about 1 kg, so 1 mg/L ≈ 1 mg/kg = 1 ppm. For liquids with a different density, ppm (by mass) = mg/L ÷ density in g/mL. Enter the density in the calculator for an exact conversion.
How do I convert ppm to percent?
Divide by 10,000. 1% = 10,000 ppm, so 250 ppm = 0.025% and 0.5% = 5,000 ppm.
How do I calculate ppm of a solution?
ppm = mass of solute ÷ total mass of solution × 1,000,000. Dissolving 0.05 g of salt in 999.95 g of water (1,000 g of solution) gives 0.05 ÷ 1,000 × 10⁶ = 50 ppm.
How do I convert gas ppm to mg/m³?
mg/m³ = ppm × M ÷ V_m, where M is the molar mass in g/mol and V_m is the molar volume of a gas: 24.47 L/mol at 25 °C and 1 atm (22.41 L/mol at 0 °C). For carbon monoxide (28.01 g/mol), 50 ppm ≈ 57.2 mg/m³ at 25 °C.
How much chemical do I add for a target ppm?
Solute mass = target ppm × solution mass ÷ 1,000,000. For water, 10 ppm in 100 L (100 kg) needs 1 g of the pure chemical. If your product is only partly active (e.g. 10% strength), divide by that fraction: 10 g of product.
What is the difference between ppm, ppb and ppt?
They are successive factors of 1,000: 1 ppm = 1,000 ppb (parts per billion) = 1,000,000 ppt (parts per trillion). 1 ppb by mass is 1 µg/kg, or about 1 µg/L in water.