What this site does. You bring a table of measurements, it gives you numbers back. This page fills the gaps: give it points you measured and it estimates the values in between, for several series at once, then plots them. It runs entirely in your browser — nothing is uploaded, nothing is stored, and there is no limit on how often you use it. If you want the reasoning rather than the answer, the interpolation article walks through the methods and where each one goes wrong.
The Input grid holds four columns: x plus three y series. Paste or import more and the extra columns are dropped with a warning. Fewer is fine — the unused columns are simply left blank.
Output x values outside the range of your data are left blank. This interpolates between your points, it does not extrapolate past them.
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