There are times when you need to calculate an intermediate value between two known values. If you have a known ratio to go by, then the process, known as linear interpolation, is easy. Our quick calculator will make sure you don't make any mistakes.

Still not sure when you need to use this? In measurement processes it is quite common to have a set of corrections for measured values. For example, you may have a thermometer and a calibration certificate for the thermometer that shows the actual temperature for several indicated temperatures. If you then measure a temperature that falls between values on the certificate, you need to interpolate the correction.

Example: You know that when your thermometer reads 30.0 degrees, it is actually 31.5 degrees and when your thermometer reads 20.0 degrees it is actually 20.2 degrees. If your thermometer reads 22.7 degrees, what is the true temperature? The true temperature is 23.251 degrees. Try it (ensure that 'default data' is selected, then click on the Clear Form button). The default data checkbox will clear to ensure that the Clear Form button works as expected the next time it is selected.
``` The formula is: D = (B - F)/(C - E)]/(A - E) + F ```

 Linear Interpolation Calculator by APLJaK A. Enter largest indicated value B. Enter corresponding corrected value C. Enter middle measured value D. Corrected value E. Enter smallest indicated value F. Enter corresponding corrected value Default Data