How to use this calculator

Linear interpolation assumes a straight line between the two reference points.

The method

y = y₁ + (x−x₁)(y₂−y₁)/(x₂−x₁)

Enter your values in the labeled fields and choose Calculate. The result panel shows the answer and supporting values when useful.

WORKED EXAMPLE INPUT

x₁: 0, y₁: 10, x₂: 20, y₂: 50

Select Calculate to evaluate these example values.

Scope and limitations

x₁ and x₂ must differ. Values outside the interval are linear extrapolations.

Common questions

Can I use different units?

Use consistent units unless this page is a unit converter. The result follows the units implied by the inputs.

Are results exact?

Displayed values may be rounded. Keep extra precision for important follow-up calculations.

Methods & verification

Formulas use standard mathematical definitions and fixed unit factors where applicable. See our methodology for numerical conventions, rounding, privacy, and limitations.