Line Graph Maker

A line graph shows how values change along an ordered axis — usually time. Paste a column of x values and one or more columns of numbers, and this maker draws each column as a line with a proper axis: real dates are spaced by the calendar, numbers by their value, and plain labels evenly. Download a PNG for documents or an SVG for the web and design tools.

How to use this tool

1. Paste CSV or cells from a spreadsheet: x values in the first column, one column per line, names in the first row.
2. Pick straight or smooth lines, markers, area fill and whether the y axis starts at zero.
3. Add a title and axis titles, choose colours and the image size.
4. Download the PNG or SVG.

Formula

y-axis step = nice((max − min) ÷ n), nice ∈ {1, 2, 5} × 10ᵏ; smooth curves use monotone cubic slopes mₖ = (sign dₖ₋₁ + sign dₖ) · min(|dₖ₋₁|, |dₖ|, ½|pₖ|)

dₖ is the slope of segment k and pₖ the slope of the parabola through three neighbouring points. Monotone smoothing never bends above a peak or below a dip, so the curve does not invent highs or lows that are not in your data. Dates are placed by their real distance, so a missing month leaves a wider gap.

Example

Monthly visitors 1,200 → 1,350 → 1,610 → 1,540 → 1,890 → 2,230 and returning visitors 310 → 610 give 2 lines with 12 points. The y axis aims for 6 intervals on a 450 px chart: (2,230 − 310) ÷ 6 = 320 rounds to a step of 500, so the axis runs 0 to 2,500; the dates span 151 days, so the x axis gets monthly ticks labelled Jan 2026 to Jun 2026.