Concentration converter
Type a mass concentration, choose the units, and see the result and the same value in every common unit. ppm and ppb are treated as parts by mass of a dilute aqueous solution whose density is about 1 kg/L, so 1 ppm equals 1 mg/L.
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How to use it
- Type a number. A dot or a comma works as the decimal separator.
- Choose the unit you have and the unit you need. The ⇄ button swaps them.
- The table shows the same concentration in all common units at once.
Assumption for ppm and ppb
Parts per million and billion are ratios by mass. This tool turns them into mg/L by assuming the solution is mostly water with a density of about 1 kg/L. That is a good approximation for drinking water, tap-water tests and dilute lab standards, and a poor one for oils, brines or concentrated solutions.
Conversion factors
Every unit is converted through milligrams per liter.
| Unit |
In mg/L |
| 1 g/L = 1 mg/mL |
1,000 |
| 1 μg/mL |
1 |
| 1 mg/dL |
10 |
| 1 ppm (water-like) |
1 |
| 1 ppb = 1 μg/L |
0.001 |
| 1 % w/v (g per 100 mL) |
10,000 |
Worked example
A water report lists nitrate at 45 ppm. Treated as a water-like solution, that is 45 mg/L, or 45,000 ppb. A 0.9 % w/v saline solution holds 0.9 × 10 = 9 g/L.
Frequently asked questions
Is 1 ppm equal to 1 mg/L?
Only for dilute water-like solutions with a density near 1 kg/L, which this tool assumes. 1 ppm by mass is 1 mg per kg of solution; in water that is about 1 mg per liter. For other liquids or strong solutions the two differ.
What does % w/v mean?
Weight per volume: grams of substance per 100 mL of solution. 1 % w/v is 1 g per 100 mL = 10 g/L = 10,000 mg/L.
How many mg/L is 1 mg/dL?
A deciliter is 0.1 L, so 1 mg/dL = 10 mg/L. This is the unit often used for blood glucose and cholesterol in lab reports.
Is μg/mL the same as mg/L?
Yes. 1 μg/mL × 1,000 mL per liter = 1,000 μg/L, and 1,000 μg is 1 mg, so 1 μg/mL = 1 mg/L.