Algebra & Equations

Linear Interpolation (2 points)

Estimate y at x between two known points.

Formula

Formula
y = y1 + (x−x1)y2−y1x2−x1

Variables

SymbolDefinitionType & rangeUnitsRole
x₁,y₁ first point real number (ℝ) input
x₂,y₂ second point real number (ℝ) input
x query real number (ℝ) input

Try it yourself

Interactive calculator
Result

Worked examples

Example 1
Givenx₁ = 0, y₁ = 0, x₂ = 10, y₂ = 100, x = 3
Result30
Example 2
Givenx₁ = 1, y₁ = 2, x₂ = 4, y₂ = 8, x = 2
Result4