Convert mg/L to ppb | milligrams per liter to parts per billion

Easily convert mg/L (milligrams per liter) to ppb (parts per billion) using this accurate and user-friendly mg/L to ppb calculator.

Whether you’re working in environmental science, water quality testing, or laboratory analysis, this tool helps you get precise results instantly by applying the standard conversion factor: 1 mg/L = 1000 ppb in water-based solutions.

mg/L to ppb Calculator

How to Convert mg/L to ppb

To convert from mg/L (milligrams per liter) to ppb (parts per billion) in water:

1 mg/L = 1000 ppb

This is based on the density of water, where 1 liter of water weighs approximately 1 kilogram, making mg/L and ppm (parts per million) numerically equivalent, and 1 ppm = 1000 ppb.

mg/L to ppb Conversion Formula

ppb = mg/L × 1000

This applies for dilute aqueous solutions (e.g., drinking water, river water), where the density is close to 1 g/mL.

Understanding the Units

• mg/L (milligrams per liter) = mass concentration (1 mg of solute in 1 L of solution).
• ppb (parts per billion) = mass ratio (1 part solute per 1 billion parts solution).

Also see: ppb to ppm calculator​

mg/L to ppb Conversion Examples

• 0.5 mg/L to ppb:
  0.5 × 1000 = 500 ppb
• 100 mg/L to ppb:
  100 × 1000 = 100,000 ppb
• 1 mg/L to ppb:
  1 × 1000 = 1000 ppb
• 5 mg/L to ppb:
  5 × 1000 = 5000 ppb

mg/L to ppb Chart

FAQs

1. Is 1 mg/L equal to 1 ppm?

Yes, for water, 1 mg/L = 1 ppm, because 1 liter of water weighs approximately 1 kilogram.

2. How many mg per L in a ppb?

In water:
1 ppb = 0.001 mg/L

To reverse the conversion:
mg/L = ppb / 1000

3. What’s the difference between mg/L and ppm?

In water, mg/L and ppm are numerically the same due to water’s density. In air or other media, conversion may vary depending on temperature and pressure.

Related:

mg/kg to percent calculator

References:

https://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.files/fileid/14285

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