Milligram/L to Parts per million Converter
Enter the value that you want to convert milligram/L (mg/L) to parts per million (ppm) or parts per million to milligram/L.Also written as MG/L to PPM conversion.
1 milligram/L = 1.0000000 parts per million
Formula: parts per million = milligram/L value × 1.0000000
MG/L to PPM — milligram/L to parts per million
10 milligram/L = 10.00000 parts per million
Popular PPM Converters:
1,000,000 parts
1 PPM
1 part per million
1 mg/L
1 milligram per liter
In water: 1 PPM = 1 mg/L = 1 mg/kg
Milligram/L to Parts per million: The Essentials
About the Milligram/L
Milligram/L (mg/L) is a unit of ppm measurement. 1 milligram/L is equal to 1.0000000 parts per million.
What is Parts per million?
Parts per million (ppm) is a unit of ppm measurement. 1 parts per million is equal to 1.0000000 milligram/L.
milligram/L to parts per million metric conversion table
| 0.01 mg/L | = | 0.01000 ppm |
| 0.1 mg/L | = | 0.10000 ppm |
| 1 mg/L | = | 1.00000 ppm |
| 2 mg/L | = | 2.00000 ppm |
| 3 mg/L | = | 3.00000 ppm |
| 4 mg/L | = | 4.00000 ppm |
| 5 mg/L | = | 5.00000 ppm |
| 6 mg/L | = | 6.00000 ppm |
| 7 mg/L | = | 7.00000 ppm |
| 8 mg/L | = | 8.00000 ppm |
| 9 mg/L | = | 9.00000 ppm |
| 10 mg/L | = | 10.00000 ppm |
| 11 mg/L | = | 11.00000 ppm |
| 12 mg/L | = | 12.00000 ppm |
| 13 mg/L | = | 13.00000 ppm |
| 14 mg/L | = | 14.00000 ppm |
| 15 mg/L | = | 15.00000 ppm |
| 16 mg/L | = | 16.00000 ppm |
| 17 mg/L | = | 17.00000 ppm |
| 18 mg/L | = | 18.00000 ppm |
| 19 mg/L | = | 19.00000 ppm |
| 20 mg/L | = | 20.00000 ppm |
| 30 mg/L | = | 30.00000 ppm |
| 40 mg/L | = | 40.00000 ppm |
| 50 mg/L | = | 50.00000 ppm |
| 60 mg/L | = | 60.00000 ppm |
| 70 mg/L | = | 70.00000 ppm |
| 80 mg/L | = | 80.00000 ppm |
| 90 mg/L | = | 90.00000 ppm |
| 100 mg/L | = | 100.00000 ppm |
| 200 mg/L | = | 200.00000 ppm |
| 300 mg/L | = | 300.00000 ppm |
| 400 mg/L | = | 400.00000 ppm |
| 500 mg/L | = | 500.00000 ppm |
| 600 mg/L | = | 600.00000 ppm |
| 700 mg/L | = | 700.00000 ppm |
| 800 mg/L | = | 800.00000 ppm |
| 900 mg/L | = | 900.00000 ppm |
| 1000 mg/L | = | 1000.00000 ppm |
How to Convert MG/L to PPM (Milligram/L to Parts per million)?
We can convert milligram/L to parts per million by using an example.
Example:
Convert 20 Milligram/L to Parts per million?
We know 1 Milligram/L = 1.0000000 parts per million; 1 Parts per million = 1.0000000 milligram/L.
20 milligram/L = ___ppm
20 × 1.0000000 = 20.00000 ppm (we know 1 milligram/L = 1.0000000 parts per million)
Answer:
20 milligram/L = 20.00000 parts per million
How to Convert Milligram/L to Parts per million
- For dilute aqueous solutions, mg/L and PPM are equivalent
- 1 mg/L = 1 PPM (in water at standard conditions)
- Simply use the same numeric value
Formula
Worked Example
Convert 75 mg/L to PPM:
75 mg/L = 75 PPM
75 mg/L = 75 PPM
Milligram/L to Parts per million Conversion Table
| Milligram/L (mg/L) | Parts per million (ppm) |
|---|---|
| 0.1 mg/L | 0.1 ppm |
| 1 mg/L | 1 ppm |
| 10 mg/L | 10 ppm |
| 50 mg/L | 50 ppm |
| 100 mg/L | 100 ppm |
| 500 mg/L | 500 ppm |
Technical Details
The mg/L to PPM conversion is a 1:1 ratio for dilute aqueous solutions. The WHO drinking water guidelines specify maximum contaminant levels in mg/L: arsenic at 0.01 mg/L (10 ppb), lead at 0.01 mg/L, fluoride at 1.5 mg/L, and nitrate at 50 mg/L. All of these are numerically identical in PPM.
Frequently Asked Questions
How do I convert mg/L to PPM?
For water, 1 mg/L = 1 PPM. The values are the same.
Is mg/L the same as ppm for all liquids?
Only for liquids with a density close to 1 kg/L (like water). For denser liquids, the conversion requires knowing the density.
How to Convert mg/L to PPM (Milligrams per Liter to Parts per Million)
Converting mg/L to ppm is the reverse of ppm-to-mg/L and follows the same principle: for dilute aqueous solutions, the values are numerically identical. This conversion is needed when entering lab results (reported in mg/L) into environmental databases or regulatory forms that require ppm notation.
- For water and dilute aqueous solutions: ppm = mg/L (direct equivalence).
- The value in mg/L numerically equals the value in ppm.
- This works because 1 mg in 1 L of water = 1 mg in ~1,000,000 mg = 1 part per million.
- Example: 250 mg/L sulfate = 250 ppm sulfate in water.
mg/L to PPM: Laboratory Results
Common laboratory water analysis results in both notations:
| Milligram/L | Parts per million |
|---|---|
| 0.01 mg/L | 0.01 ppm |
| 0.1 mg/L | 0.1 ppm |
| 1 mg/L | 1 ppm |
| 8 mg/L | 8 ppm |
| 50 mg/L | 50 ppm |
| 200 mg/L | 200 ppm |
| 500 mg/L | 500 ppm |
| 35,000 mg/L | 35,000 ppm |
Solved Examples: mg/L to PPM
Question 1: A lab reports calcium hardness at 180 mg/L CaCO₃. Express in ppm for the water softener settings.
Solution:
For water: ppm = mg/L
180 mg/L = 180 ppm
This is "moderately hard" water (121-180 ppm)
Answer: 180 mg/L = 180 ppm CaCO₃ — at the upper end of moderately hard; softener recommended.
Question 2: Dissolved oxygen in a fish pond measures 6.2 mg/L. Convert to ppm.
Solution:
For water: ppm = mg/L
6.2 mg/L = 6.2 ppm
Most fish need > 5 ppm DO to thrive
Answer: 6.2 mg/L = 6.2 ppm dissolved oxygen — adequate for warm-water fish species.
Question 3: A wastewater discharge permit requires < 30 mg/L BOD₅. The lab measures 24.7 mg/L. Express in ppm.
Solution:
For water: ppm = mg/L
24.7 mg/L = 24.7 ppm
Compare to permit limit: 24.7 < 30 ✓
Answer: 24.7 mg/L = 24.7 ppm BOD₅ — within the 30 ppm discharge permit limit.
Practice: mg/L to PPM
Try solving these on your own to test your understanding:
- Convert 12 mg/L chloride to ppm. (Answer: 12 ppm)
- A sample has 0.08 mg/L copper. Express in ppm. (Answer: 0.08 ppm)
- Convert 420 mg/L alkalinity to ppm. (Answer: 420 ppm)
- Phosphate measures 3.5 mg/L. What is that in ppm? (Answer: 3.5 ppm)
- Convert 850 mg/L TDS to ppm. (Answer: 850 ppm)
Why Labs Report mg/L While Regulations Say PPM
Analytical labs prefer mg/L because it is a direct measurement: mass of analyte per volume of sample. No density assumption is needed for the measurement itself. Regulatory agencies often use ppm because it is dimensionless and easier for the public to understand ("parts per million" is more intuitive than "milligrams per liter"). For compliance, the numerical equivalence for water means both communities can compare results directly without conversion errors.
Environmental Monitoring: Field vs. Lab Units
Field instruments (portable DO meters, TDS pens, pH meters with multi-parameter capability) display in ppm or mg/L interchangeably. However, official regulatory reporting requires specifying the unit. NPDES discharge permits typically state limits in mg/L, while drinking water consumer confidence reports often use ppm. When submitting data to EPA STORET or state databases, use mg/L — it is the standard analytical unit. The ppm designation is reserved for narrative descriptions.
Key Takeaways
- For water: 1 mg/L = 1 ppm (numerically identical).
- Labs report mg/L (mass/volume); regulations often state ppm (mass/mass ratio).
- The equivalence holds because water density ≈ 1 kg/L = 1,000,000 mg/L.
- For dense solutions (brine, wastewater sludge), ppm = mg/L ÷ density.
- Official EPA compliance reporting uses mg/L as the primary unit.
Milligram/L to Parts per million Conversion Formula
parts per million = milligram/L × 1.0000000
1 milligram/L = 1.0000000 parts per million
1 parts per million = 1.0000000 milligram/L
Reverse: milligram/L = parts per million × 1.0000000
Frequently Asked Questions
How many parts per million are in 1 milligram/L?
There are 1.0000000 parts per million in 1 milligram/L. To convert milligram/L to parts per million, multiply the value by 1.0000000.
How do I convert milligram/L to parts per million?
Multiply your milligram/L value by 1.0000000 to get the equivalent in parts per million. For example, 5 milligram/L = 5 × 1.0000000 = 5.00000 parts per million.
How do I convert parts per million to milligram/L?
Multiply your parts per million value by 1.0000000 to get the equivalent in milligram/L. Alternatively, divide by 1.0000000.
What is 10 milligram/L in parts per million?
10 milligram/L is equal to 10.00000 parts per million.
What is 100 milligram/L in parts per million?
100 milligram/L is equal to 100.00000 parts per million.