Lineweaver–Burk Enzyme Kinetics Calculator

Calculator

Substrate unit

Used for display only.

Rate unit

Used for display only.

Decimal places

Controls rounding in results and exports.

Data pairs

Provide [S] and v. The calculator uses 1/[S] and 1/v.

Use	[S] (mM)	v (µmol/min)	Notes (optional)

Tip: If your data has outliers, uncheck “Use” for those rows and refit.

Downloads become available after you run a calculation.

Example data table

A small set of substrate concentrations and observed velocities.

#	[S] (mM)	v (µmol/min)
1	0.5	0.19
2	1	0.32
3	2	0.5
4	4	0.67
5	8	0.8

Use “Fill example” to place these values into the calculator.

Formula used

The Lineweaver–Burk transform linearizes Michaelis–Menten kinetics by plotting reciprocals:

x = 1/[S]
y = 1/v
y = m·x + b

From the fitted line:

m = Km / Vmax
b = 1 / Vmax
Vmax = 1 / b
Km = m / b

How to use this calculator

Enter paired values for substrate concentration [S] and velocity v.
Keep [S] and v positive, and use consistent units.
Optionally add notes and uncheck rows you want excluded.
Press Submit to compute slope, intercept, Km, and Vmax.
Download CSV or PDF to store your dataset and results.

FAQs

1) What does the plot represent?

It graphs 1/v against 1/[S] to create a straight line. The line parameters map back to Km and Vmax for quick estimation.

2) Why must [S] and v be greater than zero?

The method uses reciprocals, so zero or negative values would be undefined or misleading. Use only positive experimental measurements.

3) Is this the best way to estimate Km and Vmax?

It is convenient, but reciprocal transforms can amplify error at low rates. For highest accuracy, compare with nonlinear fitting when possible.

4) What does R² mean here?

R² summarizes how well the straight line fits the reciprocal points. It does not directly measure fit quality in the original v versus [S] space.

5) How do I handle an outlier point?

Uncheck the “Use” box for that row and submit again. Keep a note explaining why it was excluded for transparent reporting.

6) What units will Km and Vmax have?

Km uses the same unit as [S]. Vmax uses the same unit as v. The unit fields here are for display and exports.

7) What happens if the intercept is near zero?

If b approaches zero, Vmax becomes extremely large and unstable. Review your data range, remove problematic points, and rerun the fit carefully.