Formula
v=Vmax [S]/(Km+[S]).
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Single-substrate, steady-state initial-rate model without inhibition or cooperativity.
Example Calculation
Example inputs
- Substrate concentration: 2 mmol/L
- Km: 2 mmol/L
- Vmax: 10 µmol/min
At [S]=Km=2 mmol/L, the rate is half of Vmax: 5 µmol/min.
Frequently asked questions
How do I use this calculator?
Enter substrate concentration, km, vmax. The result updates automatically. Use Reset to restore the example values.
What method does it use?
v=Vmax [S]/(Km+[S]).. Single-substrate, steady-state initial-rate model without inhibition or cooperativity.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.