Linear Interpolation Calculator
Estimate values between two known data points using the linear interpolation formula. Perfect for engineering, math, and data analysis.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Linear Interpolation Calculator
This calculator finds the unknown Y value for a given X point along a straight line between two known points (X₁, Y₁) and (X₂, Y₂).
- Enter Point 1: Fill in X₁ and Y₁ (e.g., 0 and 0).
- Enter Point 2: Fill in X₂ and Y₂ (e.g., 10 and 100).
- Enter the X to interpolate: Provide the X value you want to find Y for (e.g., 5).
- Click "Calculate" or press Enter on any field.
The result shows the interpolated Y value (rounded to 4 decimals) and the step-by-step formula.
Note: X₂ must be different from X₁. Use any numeric values (decimals allowed). No specific units required—works with any consistent scale.
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Frequently Asked Questions
Linear interpolation estimates a value between two known data points by assuming a straight line between them. It uses the formula y = y₁ + ( (x - x₁) * (y₂ - y₁) ) / (x₂ - x₁).
Yes, but extrapolation (estimating outside the range) may be less accurate as it assumes the linear trend continues beyond the known points.
The calculator will show an error because division by zero is undefined. Ensure the two X values are different.
