Bilinear Interpolation Calculator
The bilinear interpolation calculator helps you estimate the value of an unknown function based on the method of bilinear interpolation.
Interpolated y140interpolated within the known range
Fraction along40%
Slope10
Inside the known range?Yes
Equation of the liney = 10x + 0
The formula
y = y₁ + (x − x₁)(y₂ − y₁) ÷ (x₂ − x₁)
Interpolation versus extrapolation
Estimating between known points is interpolation and is usually safe. Estimating beyond them is extrapolation, and it assumes the straight-line trend continues — which is exactly the assumption most likely to be wrong. The calculator flags which one you are doing.