How It Works

This converter works in 3 steps.

Enter the value
Type the number, such as 250.
Choose its prefix
Select M, mM, µM, nM, or pM.
Read all prefixes
The converter multiplies or divides by 1,000 per step and lists each result.
Copy the needed form
Copy the value in the unit a protocol or software requires.

The Formula

The formula multiplies by 1,000 for each step down in prefix and divides by 1,000 for each step up.

Prefix ladder 1 M = 10³ mM = 10⁶ µM = 10⁹ nM = 10¹² pM

General step C_target = C_source × 10^(3 × k)

k:: Number of prefix steps from source to target (positive toward smaller prefixes)
M:: mol/L

Worked example

250 µM equals 0.25 mM, 2.5 × 10⁻⁴ M, and 250,000 nM.

Conversion Table

The conversion table shows 7 values in M, mM, µM, and nM.

Value	M	mM	µM	nM
1 M	1	1,000	1,000,000	1,000,000,000
1 mM	0.001	1	1,000	1,000,000
1 µM	10⁻⁶	0.001	1	1,000
1 nM	10⁻⁹	10⁻⁶	0.001	1
250 µM	0.00025	0.25	250	250,000
0.05 M	0.05	50	50,000	50,000,000
500 pM	5 × 10⁻¹⁰	5 × 10⁻⁷	0.0005	0.5

What Is the Molar Concentration Unit Converter?

The Molar Concentration Unit Converter is a tool that converts between molar (M), millimolar (mM), micromolar (µM), nanomolar (nM), and picomolar (pM) concentrations. Each prefix step is a factor of 1,000, so 1 M = 1,000 mM = 1,000,000 µM.

Prefix errors are the most frequent source of 1,000-fold mistakes in molecular biology and pharmacology. The converter shows every value in all 5 prefixes at once and in scientific notation, so a value such as 2.5 × 10⁻⁷ M appears as 250 nM and 0.25 µM.

Common Uses

There are 5 main uses of this converter.

Drug potency values
Pharmacologists convert IC₅₀ values from nM to µM.
Primer and probe stocks
Molecular biologists convert 100 µM stocks to 0.1 mM.
Buffer recipes
Biochemists convert 150 mM NaCl to 0.15 M for calculations.
Software input
Users enter concentrations in the unit an instrument program expects.
Literature comparison
Researchers compare reported values across papers.

Molar Concentration Unit Converter