ToolsEnvironmentalContamination Assessment

PPM / mg/L Converter

Convert between ppm, mg/L, µg/L, and % for contaminated land and water quality assessments. Instant conversion for environmental sampling results.

Last updated 14 April 2026

About this tool

Convert between common concentration units used in contaminated land assessment and water quality testing. Supports ppm, mg/L, µg/L (ppb), and percentage — the units you encounter daily in lab reports and screening criteria.

For dilute aqueous solutions (groundwater, leachate, surface water), 1 ppm is equivalent to 1 mg/L. This assumes a solution density of approximately 1 kg/L, which is valid for most environmental water samples.

Eight conversion directions are available in a single tool, so you don't need to remember which way the factor goes when comparing lab results against Generic Assessment Criteria or Drinking Water Standards.

How to use this tool

1. Select the conversion direction — e.g. ppm → mg/L, µg/L → ppm, % → ppm.

2. Enter your value — the result updates instantly.

3. Check the conversion table — the reference table shows all factors at a glance.

Technical information

1 ppm = 1 mg/L (dilute aqueous, density ≈ 1 kg/L)

1 ppm = 1,000 µg/L

1 % = 10,000 ppm

The ppm ≈ mg/L equivalence holds for water-based samples at environmental concentrations. For high-salinity brines, non-aqueous phase liquids, or soil concentrations expressed as mg/kg, the density assumption should be checked.

Limitations

The 1 ppm = 1 mg/L equivalence assumes dilute aqueous solution with density ≈ 1 kg/L. This is valid for most groundwater and surface water samples but not for concentrated solutions, brines, or non-aqueous liquids.

For soil concentrations, ppm is equivalent to mg/kg (not mg/L). The tool does not perform soil-to-water partitioning calculations.

Revision history

14 April 2026: Initial release

Disclaimer

This tool is provided for educational and general information purposes only. It is not a substitute for professional engineering advice, design or verification.

Diggy and its contributors are not licensed engineering consultants and no results generated by this tool should be used directly for construction, design or safety-critical decisions.

All values and outputs are based on published empirical correlations and should be independently checked and confirmed by a qualified geotechnical engineer before use.

By using this tool, you accept full responsibility for how you interpret and apply the information provided.

Spotted an error? Let us know.

Conversion

Value (ppm)

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