Lineweaver-Burk Calculator

Vmax and Km from a double-reciprocal fit.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

Substrate concentrations

Comma separated. All must be above zero — the plot takes reciprocals.

Measured velocity at each

Must line up one-to-one with the concentrations.

Reciprocal transformation weights the noisiest points most heavily. Use non-linear regression for parameters you intend to publish.

From the double-reciprocal fit

Vmax 99.9975

Km 4.9998 · R² = 1.00000

Vmax99.9975

Km4.99977

y-intercept (1/Vmax)0.01

Slope (Km/Vmax)0.049999

R²1.000000

Points used5

The double-reciprocal plot turns the Michaelis-Menten hyperbola into a straight line: 1/v against 1/[S], with intercept 1/Vmax and slope Km/Vmax. It is worth knowing that this is a poor way to fit real data. Taking reciprocals compresses the well-measured high-substrate points into a cluster near the origin and stretches the noisy low-substrate ones far out, so the least reliable measurements dominate the regression. A visually excellent line can hide a badly biased Vmax. Use it to visualise inhibition patterns (competitive inhibition shares a y-intercept, non-competitive shares an x-intercept) and use non-linear regression on the untransformed data for the actual numbers.

How the Lineweaver-Burk Calculator works

Paste your substrate concentrations and velocities and this fits the double-reciprocal line, returning Vmax from the intercept and Km from the slope. The page is also explicit that this is a poor way to fit real data, and why.

Also known as: double reciprocal plot calculator · km vmax from lineweaver burk · 1/v vs 1/s plot · enzyme kinetics plot calculator

Where to go next

The Lineweaver-Burk question rarely arrives on its own. These are the ones that usually come with it:

Michaelis-Menten Calculator — Velocity, saturation and catalytic efficiency.
Calibration Curve Calculator — Least-squares standard curve, then read an unknown off it.
Speed Distance Time Calculator — Any one of the three from the other two, in four units.
Acceleration Calculator — Acceleration in m/s² and in g, which is the legible one.

Sources

Frequently asked questions

How does a Lineweaver-Burk plot work?

Plot 1/v against 1/[S]. The y-intercept is 1/Vmax and the slope is Km/Vmax, so both parameters fall out of a straight-line fit.

Why is it considered a bad method?

Because taking reciprocals distorts the error structure. Well-measured high-substrate points cluster near the origin while noisy low-substrate points stretch far out, so the least reliable data dominate the regression. Non-linear regression on untransformed data is correct.

Why is it still taught?

Because it makes inhibition patterns visible at a glance. Competitive inhibitors share a y-intercept, non-competitive share an x-intercept, and uncompetitive give parallel lines — that diagnostic value is real even when the numbers are not.

What are the alternatives?

Eadie-Hofstee and Hanes-Woolf both distort the errors less, and direct non-linear fitting of the Michaelis-Menten equation distorts them not at all. Use the plot to look, and the fit to measure.

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