If you have a few data points and need to find a missing value use the Linear Interpolation & Extrapolation Calculator to estimate values between or beyond known data.
Table of Contents
🙋 What Does the Calculator Do?
This tool helps you:
- Add as many (x, y) points as you need
- Enter an x-value to estimate a y-value for
- Automatically calculate the y-value using:
- Linear interpolation (if x is between known points)
- Linear extrapolation (if x is outside the range)
It does all the math for you!
⚙️ Linear Interpolation & Extrapolation Calculator
📏 Example Use
Imagine you're given three known points (inputs):
- (1, 10)
- (2, 20)
- (4, 40)
If you want to find the value at x = 3, the calculator will interpolate between (2, 20) and (4, 40), returning y = 30.
If instead you enter x = 5, the calculator will extrapolate beyond (4, 40), using the last two points to return y = 50.
To use the Calculator in this case enter the number of points 3.
- x1 = 1; y1 = 10
- x2 = 2; y1 = 20
- x3 = 4; y3 = 40
Next enter 3 and the tool will calculate the corresponding y value
🧮 How Does It Work?
The calculator uses a simple linear formula:
y = y₀ + (x - x₀) * (y₁ - y₀) / (x₁ - x₀)It finds the two closest points around your chosen x-value and calculates the corresponding y.
If your x-value is:
- Inside the known range → it interpolates
- Outside the known range → it extrapolates
You’ll see a label next to the result telling you which method was used.
🌐 Who Can Use It?
This tool is great for:
- 📘 Students studying math or physics
- 🛠️ Engineers estimating values between measurements
- 📊 Researchers projecting trends
- 💼 Anyone working with graphs or charts