Linear Interpolation Calculator
Estimate a value between two known data points.
Your inputs
Calculation results
Formula & assumptions
y = y₁ + (x−x₁)(y₂−y₁)/(x₂−x₁).
Values use the specified units. Calculations use floating-point arithmetic. Check input measurements and formula assumptions before applying the result.
Compare your scenarios
Save up to five results to compare changes side by side. Scenarios stay in this tab until you clear or reload it.
Using Linear Interpolation Calculator
Estimate a value between two known data points.
- Enter first x, first y, second x, second y, target x using the units printed under each field.
- Choose Calculate, or enable live updates. Review the result labels and formula assumptions.
- Save scenarios to compare up to five variations, then copy the report or download JSON or CSV.
Example
First X: 0 units First Y: 10 units Second X: 10 units Second Y: 30 units Target X: 4 units Interpolated Y: 18 Position fraction: 0.4 Extrapolation flag · 1 means outside: 0
Questions & answers
What does Linear Interpolation Calculator calculate?
Estimate a value between two known data points.
Which units should I enter?
First X uses units. First Y uses units. Second X uses units. Second Y uses units. Target X uses units. Convert values to these units before calculating.
Which formula does it use?
y = y₁ + (x−x₁)(y₂−y₁)/(x₂−x₁).
What does the included example show?
First X: 0 units; First Y: 10 units; Second X: 10 units; Second Y: 30 units; Target X: 4 units. Result: Interpolated Y = 18; Position fraction = 0.4; Extrapolation flag · 1 means outside = 0.
Can I compare different settings?
Yes. Save a scenario, change the inputs and save another result. Up to five scenarios are compared in this tab; they disappear when you reload or leave.
Can I export the calculation?
Copy the JSON report or download JSON and CSV with inputs, result labels and numeric values. Processing uses local JavaScript; no calculation request is sent to our server. Displayed values use up to 10 significant digits; exports retain JavaScript numeric precision.
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