Concentration Converter Free Online
Convert mass concentration between g/L, mg/L, μg/L, ppm, ppb, and percent w/v. Note: molar units (mol/L) require knowing the molecular weight — see FAQ.
All Units
Pro — bulk batch conversion, API access, history & favorites
API access · Priority queue · Team workspace
Related Tools
Concentration Converter Features
Lab Ready
Standard mass-based units used in chemistry, biology, environmental science, and clinical labs (mg/dL for blood glucose).
9 Units
g/L, mg/L, μg/L, ng/L, ppm, ppb, % w/v, ‰, mg/dL. Covers labs from pollution monitoring (ppb) to industrial chemistry (% w/v).
Aqueous ppm
For dilute aqueous solutions (where density ≈ 1 g/mL), 1 ppm = 1 mg/L exactly. This is the standard approximation.
Live Conversion
Type a value, see all units instantly.
Swap Units
Quick reverse with the swap button.
100% Private
All math runs in your browser.
Free vs Pro
| Feature | Free | Pro |
|---|---|---|
| Full concentration conversion | ||
| Live conversion | ||
| All-units result panel | ||
| Bulk CSV / Excel conversion | — | |
| REST API access | — | |
| Custom precision settings | — |
Frequently Asked Questions
For dilute aqueous solutions (water ~ 1 g/mL), yes — 1 ppm = 1 mg/L. For non-aqueous or concentrated solutions, you need the actual density: ppm = mg / kg solution.
Multiply by molecular weight in g/mol, then by 1000. Example: 0.1 mol/L NaCl (MW 58.44) = 0.1 × 58.44 × 1000 = 5844 mg/L = 5.844 g/L. This tool focuses on mass units — for molar conversion, multiply by your compound's MW.
Percent weight per volume = grams of solute per 100 mL of solution. So 5% w/v glucose = 5 g per 100 mL = 50 g/L = 50,000 mg/L. Common in pharmacy and biochem.
Clinical chemistry, especially blood glucose, cholesterol, and BUN. 100 mg/dL glucose is normal fasting. To convert to mmol/L for glucose, divide by 18 (MW correction).
Parts per billion = μg/L for water. Used for trace contaminants like lead in drinking water (US EPA limit = 15 ppb = 15 μg/L), pesticides, and pharmaceuticals.