Calculated Target Y
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Linear Interpolation Calculator
Estimate unknown values between two known coordinates with formula visibility, extrapolation warnings, and a consistent site shell.
Dynamic Status
-Step-by-Step Formula
y = y₁ + ((x - x₁) / (x₂ - x₁)) * (y₂ - y₁)
Linear interpolation, explained clearly
Linear interpolation estimates a value between two known points. It is a simple and practical method for tables, charts, engineering lookups, and business planning when the data changes smoothly. After you bridge two anchors, stress-test whether the trend should really be straight using a linear regression calculator, or contrast the additive gap with ratio-based growth in a geometric sequence calculator.
Formula and workflow
Use the slope between the two points, then apply that slope to the target x-value. If the target x falls outside the known range, the same math becomes extrapolation and is less reliable.
| Term | Meaning | Example |
|---|---|---|
| x₁, y₁ | First known point | 110, 1.0516 |
| x₂, y₂ | Second known point | 120, 1.0603 |
| x | Target input | 115 |
When to use it
It works well for lookup tables, calibration values, and small gaps in data. It is not ideal for sharply curved trends, discontinuities, or noisy measurements.
FAQs
What is the difference between interpolation and extrapolation?
Interpolation stays inside the known range; extrapolation goes outside it.
Does the point order matter?
No, as long as each x stays matched to its y.
Why would the answer be unreliable?
If the data is curved, a straight-line estimate can drift.
Can I use decimal values?
Yes, the calculator supports decimals and negative numbers.
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