Browser-local utility
Interpolation Calculator
Perform forward or inverse two-point linear interpolation with explicit extrapolation handling.
Inputs
Result
Initializing.
Method and worked example
Forward: y = y1 + (x − x1)(y2 − y1)/(x2 − x1). Inverse swaps the coordinate roles. Endpoints may be ascending or descending. For (0,10), (20,30), target x=5, y=15.
Scope and limitations
Two-point linear interpolation only—not polynomial interpolation, splines, regression, curve fitting, or forecasting. Outside targets are rejected unless extrapolation is explicitly enabled.