Linear Interpolation Calculator
Enter two known (x, y) data points and a target x-value to instantly calculate the linearly interpolated y-value.
Enter Data Points
First Known Point
Second Known Point
Target Value
Result
Fill in the fields above and click Calculate.
Interpolated y at x = —
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Formula Breakdown
Note: x is outside [x1, x2] — this is extrapolation, not interpolation.
Lerp Formula
y = y1 + (x − x1) × (y2 − y1) / (x2 − x1)
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Summary
Enter two known (x, y) data points and a target x-value to instantly calculate the linearly interpolated y-value.
How it works
- Enter the x and y coordinates of your first known point (x1, y1).
- Enter the x and y coordinates of your second known point (x2, y2).
- Enter the target x-value you want to interpolate at.
- The calculator applies the lerp formula and displays the interpolated y-value.
- Swap the input order or try multiple x targets without reloading.
Use cases
- Estimate a temperature reading between two recorded sensor values.
- Find a price at an intermediate date using two known price points.
- Interpolate color channel values in graphics and animation.
- Calculate an unknown measurement in an engineering data table.
- Determine intermediate RPM or torque values on a performance curve.
- Estimate population figures between two census years.
- Solve homework or exam problems involving lerp.
- Quickly check manual interpolation arithmetic.
Frequently Asked Questions
Last updated: 2026-06-10 ·
Reviewed by Nham Vu