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Function Grapher — Free Graph Plotting Tool
Plot functions online: pick a function — get an interactive graph with zoom and pan.
MathsUK has a free online function grapher — a graph plotter that draws any function in a single click, with nothing to install and no sign-up. Choose a function type from the list — straight line, parabola, sine, logarithm and more — and get an instant interactive graph with zoom, drag and control over parameters like a, b and c. The tool is built for students who want to see how a graph changes as a coefficient changes, and for anyone who needs to plot a function quickly for homework or exam revision.
A few example uses:
- Want to see what y = x² looks like next to y = x² + 4? Choose "parabola" and drag the c slider — watch the graph shift upward in real time.
- Need to plot y = sin(x) and understand amplitude and period? Choose "sine" from the list, or just click the ready-made example in the "Trigonometry" category.
- Want to explore a function with an asymptote, like y = 1/x? Choose "hyperbola" and see how the graph behaves near x = 0.
f(x) = a·x² + b·x + c
a1
b0
c0
View: x ∈ [-10, 10], y ∈ [-10, 10]
Function information
f(0) = 0
f(1) = 1
Domain: all real numbers.
Examples
How to use it
- Choose a function from the dropdown list — straight line, parabola, sine and more.
- Some functions include sliders for parameters a, b, c. Drag them and watch how the graph changes.
- Use the zoom and pan buttons to change the visible range.
- The info card shows key points: f(0), f(1) and a note on the domain.
- Clicking "Reset" returns the parameters and range to their default values.
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✍️ Written by the MathsUK teamChecked against the National Curriculum and GCSE specifications