Interpolate Between Data Points
Enter the X value for which you want to find the corresponding Y value.
Complete guide to mathematical interpolation methods, engineering tables, and accuracy considerations.
Linear interpolation estimates an intermediate value between two known data points by assuming a straight-line relationship. It is widely used in engineering to extract values from property tables, pipe schedule data, and correction factor charts.
The interpolated value y is calculated as y = y₁ + (x − x₁) × (y₂ − y₁) / (x₂ − x₁), where (x₁, y₁) and (x₂, y₂) are the known data points and x is the target value. The method assumes the relationship between points is approximately linear.
Interpolation estimates values within the range of known data points and is generally reliable. Extrapolation estimates values beyond the known range and becomes increasingly uncertain as the distance from the data increases, requiring engineering judgment on validity.