BioinformaticsBrowser-sidemg/mL ↔ µM

Protein Concentration Calculator

Convert protein concentration between mg/mL and molarity using molecular weight, then estimate nmol for your sample volume.

100% browser-sideTwo-way conversionInstant recalculation
Inputs
Enter a molecular weight and one concentration. Sample volume is optional.
Conversion direction
Common proteins:
Optional

Only needed for total nmol and total mg. Concentration results appear without it.

Results
Every equivalent unit updates as you type.
Molarity
20.00µM
from 1.000 mg/mL at 50.00 kDa

Mass concentration

Molar concentration

Sample totals

µM = (mg/mL × 1000) / kDa  ·  mg/mL = (µM × kDa) / 1000  ·  1 µM in 1 mL = 1 nmol

Try a worked example

Load any scenario straight into the calculator above.

Why this calculator is useful

Protein concentration shows up in prep, QC, chromatography, assay design, and notebook-based analysis.

Two-way conversion
Convert from protein mass concentration to molarity, or enter a molar value and recover the equivalent mass concentration.
Sample-volume aware
Estimate total nmol and total mg in the sample volume you provide, which is useful for prep and downstream experiments.
Browser-side calculation
Everything runs locally in your browser. No upload, no login, and no dependency on a server-side calculator.
Unit reference
These are the conventions the calculator uses.

mg/mL

Numerically equal to g/L for aqueous protein solutions.

µg/mL

1,000 µg/mL = 1 mg/mL.

µM

1 µM in 1 mL equals 1 nmol.

kDa

1 kDa = 1,000 g/mol, which makes the conversion straightforward.

Quick conversion rule
For protein concentration in mg/mL, use the molecular weight in kDa to move between mass and molar units.
µM = (mg/mL × 1000) / kDa
mg/mL = (µM × kDa) / 1000
1 µM in 1 mL = 1 nmol
Assumption: 1 Da is treated as 1 g/mol and the molecular weight you enter is used as-is. This is meant for quick concentration conversion, not extinction-coefficient-based quantification.

Frequently asked questions

A few quick answers before you use the calculator in a lab or notebook workflow.

It converts protein concentration between mass units and molarity using the molecular weight you enter. It also estimates total nmol in the sample volume.

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