How to convert molar to millimolar?
Type a value in either box, and the answer shows it in the other unit as you type.
- Millimolar (mM)
- 1,000
1 M = 1,000 mM.
Millimolar (mM): 1,000. 1 M = 1,000 mM.
Millimolar (mM) by molar (M)
How to calculate
Converts molar (M) to millimolar (mM) and back, with the exact unit definitions.
Example with the default inputs (Molar (M) 1): 1 M = 1,000 mM.
Formula: mM = M × 1000 (the same as M ÷ 0.001)
- 1 molar = 1000 millimolar, from the exact definitions in NIST SP 811.
- Exact on the typed decimals: at most 6 decimal places (6 significant digits below 0.0001), rounded half up.
Worked examples
Each example is checked against the calculator on every build.
- Molar (M) 1 gives Millimolar (mM) 1,000.Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8
- Molar (M) 0.15 gives Millimolar (mM) 150.Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8
- Millimolar (mM) 150 gives Molar (M) 0.15.Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8
Other questions people ask
How many millimolar are in a molar?
1 molar is 1,000 millimolar, from the exact unit definitions (NIST SP 811).
How do I convert molar to millimolar?
Multiply by 1,000: mM = M × 1000 (the same as M ÷ 0.001). For example, 1 M × 1,000 = 1,000 mM.
How do I convert millimolar back to molar?
Multiply by 0.001, or type the millimolar into the second box and the converter works it out. 1 millimolar is 0.001 molar.
What does molar (M) mean?
Moles of a substance per liter of solution: 1 M = 1 mol/L (IUPAC, amount concentration). Millimolar is a thousandth of that: 1 mM = 1 mmol/L.
What is 0.15 M in mM?
0.15 × 1,000 = 150 mM. Normal saline (9 g of NaCl per liter) is about 0.154 M, or 154 mM.
Do I need the molar mass?
No. M to mM only moves the decimal point three places. To go from grams per liter to molar you need the molar mass; the molarity calculator does that.