An interpolation calculator is a mathematical tool that estimates an unknown value that falls between two known data points. Linear interpolation is the most basic form, using the formula to find an intermediate value based on a straight-line assumption between the two known points. More advanced versions perform polynomial interpolation, spline interpolation, or Lagrange interpolation to account for curved data relationships. Interpolation is widely used in engineering, finance, data analysis, and science to fill gaps in data sets or estimate missing readings in tables, sensor measurements, or experimental results.
Interpolation calculators are commonly used in fields such as thermodynamics, where engineers reference steam tables and need values at intermediate pressures or temperatures. Financial analysts use interpolation to estimate bond yields, while scientists apply it to calibration curves in laboratory settings. Online interpolation calculators allow users to enter two or more known data points and an x-value to receive the corresponding interpolated y-value. Many also support tabular data input for more complex polynomial or natural cubic spline interpolation. Understanding when to apply linear versus polynomial interpolation depends on the nature of the data and the accuracy required for a given scientific or engineering application.