How to use the competitive inhibition calculator
Find the apparent Km with a competitive inhibitor. Enter km, inhibitor concentration, ki in the fields above; the apparent km, fold increase are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- Km — Km (mM)
- I — Inhibitor concentration (mM)
- Ki — Ki (mM)
Worked example
With km = 2 mM, inhibitor concentration = 1 mM, ki = 0.5 mM, the calculator gives apparent km ≈ 6 mM; fold increase ≈ 3.
Frequently asked questions
What is the formula for the competitive inhibition calculation?
Apparent Km (mM) = Km × (1+I / Ki). Fold increase = 1+I / Ki. Here Km is km (mM), I is inhibitor concentration (mM), Ki is ki (mM).
What inputs do I need for the competitive inhibition calculator?
You need km in mM, inhibitor concentration in mM, ki in mM. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.