Calculation steps will appear here.
Calculator inputs
Batch conversion
Each row can use a different concentration, molecular weight, substance, and note.
| Sample | Direction | Value | Input unit | Molecular weight | Substance | Output unit | Result | Notes | Remove |
|---|
Formula used
nmol/L = (ng/mL × 1000) ÷ molecular weight (g/mol)
ng/mL = (nmol/L × molecular weight (g/mol)) ÷ 1000
Mass concentration and molar concentration describe different quantities. Molecular weight connects measured mass with the number of molecules. The correct molecular form must always be selected carefully.
How to use this calculator
- Select the required conversion direction.
- Choose a substance preset or enter custom details.
- Enter the concentration and its current unit.
- Confirm the molecular weight in grams per mole.
- Select an output unit and preferred precision.
- Add reference range values when needed.
- Press calculate and review every displayed conversion step.
Preset molecular weights improve speed but still require verification. Different salts, hydrates, and metabolites may have different weights. Check the laboratory method before using clinical results elsewhere.
Worked examples
| Substance | Input | Molecular weight | Calculation | Result |
|---|---|---|---|---|
| Custom compound | 5 ng/mL | 250 g/mol | (5 × 1000) ÷ 250 | 20 nmol/L |
| Testosterone | 3 ng/mL | 288.42 g/mol | (3 × 1000) ÷ 288.42 | 10.4015 nmol/L |
| Estradiol | 0.1 ng/mL | 272.38 g/mol | (0.1 × 1000) ÷ 272.38 | 0.3671 nmol/L |
Unit relationships
| Unit | Equivalent base value | Type |
|---|---|---|
| 1 pg/mL | 0.001 ng/mL | Mass concentration |
| 1 µg/L | 1 ng/mL | Mass concentration |
| 1 mg/L | 1000 ng/mL | Mass concentration |
| 1 pmol/L | 0.001 nmol/L | Molar concentration |
| 1 µmol/L | 1000 nmol/L | Molar concentration |
| 1 mmol/L | 1,000,000 nmol/L | Molar concentration |
Common mistakes
- Using one universal factor for every substance.
- Entering molecular weight in kilograms per mole.
- Confusing ng/mL with ng/L or µg/L.
- Using a salt weight instead of analyte weight.
- Rounding before completing the full calculation.
- Comparing different laboratory methods without checking references.
Unit prefixes can change values by factors of thousands. Early rounding can also distort very small concentrations. Keep extra digits until the final reported answer appears.
Frequently asked questions
Can ng/mL convert directly to nmol/L?
Yes, but the substance molecular weight is required. Mass units alone cannot reveal the number of molecules. Enter the exact molecular form for dependable conversion results.
Why does molecular weight matter?
Molecular weight states the mass of one mole. Heavier molecules produce fewer moles from equal measured mass. Therefore, each compound needs its own conversion factor.
Is µg/L equal to ng/mL?
Yes, their numerical values are exactly equal. Both describe the same mass within equivalent liquid volumes. The calculator handles this relationship before molar conversion begins.
Can I convert nmol/L back to ng/mL?
Yes, select the molar-to-mass conversion direction. The calculator multiplies by molecular weight and divides by one thousand. Reverse verification also checks the original submitted value.
What molecular weight should I enter?
Use the molecular weight matching the reported analyte. Salts, hydrates, and metabolites may require different molecular weights. Consult the assay documentation when uncertainty remains present.
Does the calculator accept scientific notation?
Yes, numerical fields accept values like 1.2e-3. Scientific notation is also displayed beside each main result. This helps with extremely small or large concentrations.
How does automatic unit scaling work?
Automatic scaling selects a more readable output unit. It tries keeping the displayed number within practical limits. The underlying base conversion remains unchanged and fully traceable.
Can reference ranges be converted?
Yes, enter optional low and high range values. Both values use the selected input and output units. The converted interval appears with the main calculation result.
Can several samples use different substances?
Yes, every batch row supports separate molecular weights. Sample names, notes, units, and directions are also independent. This supports mixed datasets without changing the main form.
Are preset molecular weights always exact?
Presets use common molecular formulas and reference values. Laboratories may measure another form or related metabolite. Verify the value before making important clinical interpretations.
Is this calculator medical advice?
No, it only performs mathematical unit conversions. Laboratory interpretation depends on methods, ranges, history, and context. Qualified healthcare professionals should review clinical decisions carefully.
This calculator provides educational mathematical conversions only. It does not diagnose conditions or replace professional advice. Confirm molecular weights, units, methods, and reference ranges independently.