Make a printable number line with negatives, decimals or fractions

Because computers cannot store 0.1 exactly. In binary floating point, 0.1 is a recurring value that gets rounded, so adding it ten times gives 0.9999999999999999 rather than 1, and the check “have we reached the end?” fails on the last mark. What you see is a line with nine divisions instead of ten, or a final tick sitting a hair inside the arrowhead, or a label reading 0.7000000000000001. This tool never adds decimals: every value you type is converted to a whole-number fraction — 0.1 becomes 1/10 — and every position is computed as an exact ratio, with a decimal appearing only at the very end when a coordinate is written to the page. It is the same discipline the loan calculators on this site use to keep a 360-month schedule ending at exactly zero.

Type a negative start: −10 to 10, or −5 to 5, or −20 to 20 in twos. The line is drawn as one continuous axis with zero wherever it falls, which for a symmetric range is the middle, and the negative labels carry their minus signs. If you want pupils to work out where zero is, use “Ends only” so the line shows −5 and 5 and nothing between, or “Empty boxes” so every labelled position gets a box including zero. There is deliberately no special emphasis on zero — no thicker tick, no different colour — because the point of a number line crossing zero is that zero is one number among the others rather than a boundary, and printing it differently teaches the opposite.

Yes, and the labels are printed as mixed numbers. A line from 0 to 2 in halves reads 0, 1/2, 1, 1 1/2, 2 — not 0/2, 1/2, 2/2, 3/2, 4/2, which is what you get from a tool that formats every value the same way. Values that land on a whole number lose their fraction entirely, and fractions are reduced, so a line in quarters labels the halfway point 1/2 rather than 2/4. Type intervals as fractions too: 1/4, 1/3, 1/8. Thirds and sixths are worth pointing out, because they cannot be written exactly as decimals — a line from 0 to 1 in thirds is exact in fraction mode and rounds to 0.333 and 0.667 in decimal mode, which is a fine illustration of why fractions exist and a poor label if you did not intend it.

It prints the line, the marks and a small empty box under every labelled position, so the sheet becomes the exercise rather than the answer. It is the version to use for assessing whether a pupil can place values on a line they have not been given, and it works particularly well combined with divisions: labelled positions every 1 with five divisions between gives a line where the boxes are whole numbers and the small marks are fifths, and filling in the boxes requires counting the divisions rather than remembering the sequence. The boxes are drawn on every labelled position including the two ends, on purpose — a line that hands you its first and last values has already answered most of the question.

The line is drawn across the full width of the page inside your margins, less a small pad at each end so the arrowheads and the outermost labels are not clipped. On A4 landscape with 15 mm margins that comes to 253 mm; the tool prints the exact figure, along with the distance between two labelled marks. Measure a single gap between labelled marks rather than the whole line: a print dialog set to “fit to page” typically shrinks by three to six percent, which is 8 to 15 mm across a full line and easy to argue with, but on a 25 mm gap it shows up as a clean millimetre and there is nothing to argue with.

Sixty labelled marks and four hundred marks in total, and both limits are about the paper rather than the software. A labelled mark needs roughly 8 mm of horizontal room before the numbers start touching each other; across a 253 mm line that is about thirty comfortably and sixty at the point where two-digit labels collide. Small division marks need about 0.6 mm to stay separable at normal line weights. Past those numbers the tool would happily draw something, and it would be an unreadable grey band rather than a number line. If you need 0 to 100 in ones, the answer is usually two sheets of 0–50, or one line labelled every 10 with ten divisions between — which is the same information and can actually be read.

Because a number line is one long horizontal thing and everything useful about it scales with its length. On A4 portrait the line is 180 mm; on landscape it is 267 mm, half as long again, and that extra length goes straight into the space between marks — which is the only thing that decides whether the line is readable from a distance or has to be held at arm’s length. Portrait is still there and is the right choice when you want many short lines on one sheet, or when the sheet is going into a portrait workbook alongside other work. Either way the marks are positioned by the same arithmetic; only the width they are spread across changes.

There is a single instruction line printed once at the top — enough for “Mark 3/4 on each line” or “Estimate where 0.35 goes” — plus an optional name and date row. It is deliberately one line rather than a rich text box. A worksheet generator that grows a question editor becomes a worksheet generator that people fight with, and the thing this page does well is get the geometry of the line exactly right; the wording around it is usually easier to add by hand, or in the document you are pasting the downloaded SVG into.