Printed graph paper measures the wrong size because the print dialog scaled it to fit — “Fit to page” typically shrinks a sheet to 94–97%, turning a 5mm grid into 4.7mm. The fix is choosing Actual size / 100% and matching the document’s paper size to the paper in the tray; everything below is diagnosis for when that isn’t enough.

The scaling math

Printer drivers shrink documents for a benign reason: most printers can’t print to the sheet’s physical edge, so “fit” guarantees nothing clips. For a photo that’s a favor — for a measuring grid it’s sabotage:

Printed at	A 5mm grid becomes	A ¼-inch grid becomes
100% (Actual size)	5.00mm	0.250in
97%	4.85mm	0.243in
94%	4.70mm	0.235in
90%	4.50mm	0.225in

A 4% shrink sounds trivial until you’re plotting data, cutting fabric pieces, or a student measures a line “5mm” that is really 4.7mm on every axis.

The four causes, in order of likelihood

1. Fit-to-page scaling (≈90% of cases). Every browser and driver defaults to it on mismatched paper. Set Actual size or 100% explicitly — the generator emits a true-size sheet; don’t let the dialog rescale it.
2. A4 vs Letter mismatch. A4 is 210×297mm; Letter is 216×279mm — wider but 18mm shorter. An A4 sheet “fit” onto Letter scales to ~94% to recover the height. Match sizes end-to-end: generate for Letter if you print on Letter.
3. A “printable area” margin option. Some drivers add “scale to printable area” separately from fit-to-page — the same shrink under another name. Turn it off; edge clipping of partial squares is harmless.
4. The browser ignoring the document’s page size. Chrome and Edge honor @page { size }; Firefox ignores it and falls back to whatever paper size the dialog says — which silently reintroduces scaling. On Firefox, set the paper size manually at 100%, or print from Chromium.

Verify, don’t trust

After any fix, measure: 10 squares of a 5mm grid = exactly 50mm; 4 squares of ¼-inch = exactly 1 inch. Measure across many squares — single-square checks hide sub-millimeter error. The sheet’s outermost row may clip inside the printer’s unprintable border; that doesn’t affect the scale of what’s on the page.

The generator draws every grid natively in millimeters and injects a matching @page size, so a correct dialog setting is the only variable left. For which grid suits which job, the paper types guide maps all ten.

Frequently asked questions

Why does my printed graph paper not measure correctly?

Almost always because the print dialog's scaling was set to Fit to page, Fit to printable area or Shrink to fit — any of which shrinks the whole sheet, typically to 94–97%, so a 5mm grid lands at ~4.7mm. Set scaling to Actual size or 100% and the grid measures true. Check with a ruler across 10 squares: 10 × 5mm should span exactly 50mm.

How do I print graph paper at actual size?

In the print dialog, find the scale setting and choose Actual size / 100% / Custom: 100 (wording varies by browser and driver). Make sure the paper size selected in the dialog matches the paper the document was made for — A4 document to A4 paper. Then ignore any 'margins may clip' warnings; grid paper is meant to use the full sheet.

A4 vs Letter — does it matter for printing?

Yes, and it's the second most common cause. A4 is 210×297mm; US Letter is 216×279mm — wider but 18mm shorter. Printing an A4 document 'fit to page' onto Letter scales it to ~94% to squeeze the extra height in. Select the paper size that matches your sheet, or generate the document for your paper in the first place — the generator offers A4, Letter, A3, Tabloid and custom sizes.

Chrome vs Firefox — which prints graph paper more accurately?

Chrome and Edge respect the document's @page size declaration, so a generated sheet arrives at true scale with less fiddling. Firefox historically ignores @page { size }, so you must manually set the correct paper size and 100% scale in its print dialog — and on some driver combinations it still adds scaling. If measurements matter (engineering, sewing patterns, school rulers), print from Chrome/Edge and verify with a ruler anyway.

How can I check if my printout is true scale?

Ruler test: measure across a known number of squares — 10 squares of a 5mm grid = exactly 50mm; 4 squares of a ¼-inch grid = exactly 1 inch. Measuring a single square hides small errors. If you're consistently 1–2mm short over 50mm, the sheet printed at ~96–98% — find the scaling option and set it to 100%.

Why is there a blank border even at 100%?

Most printers have a small unprintable margin — typically 3–5mm on inkjets, ~4mm on lasers — that no setting removes; it's hardware. A true-scale grid still prints correctly inside that border (the outermost partial squares get clipped, inner squares stay accurate). If you need grid to the physical edge, use a borderless-capable printer or trim the sheet.