The one setting that matters
Every sheet on this site is a PDF with an exact page size. PDF measures in points of 1/72 inch, so a US Letter page is 612 × 792 points and an A4 page 595.3 × 841.9 points. Nothing in the file changes when you print it. The only thing that can change the size is a scaling option in the print dialog. Set it to 100% or Actual size and the printer reproduces the measurements. Leave it on Fit to page, Fit to printable area or Shrink oversized pages and everything comes out a few percent smaller, which is enough to spoil a grid, a pattern or a ruler.
Our PDFs also carry the PDF standard’s “no scaling” preference (PrintScaling None), which tells viewers that honour it, such as Adobe Acrobat, to start the dialog at actual size. Browsers don’t always read it, so always check the dialog yourself.
How much does Fit to page shrink a sheet?
Fit to page doesn’t pick a random percentage. It shrinks the page until it fits inside the printer’s unprintable edge, the strip around the paper the print head or toner can’t reach. The scale is simply the paper size minus that edge on both sides, divided by the paper size, taking whichever direction is tighter. Here it is for common edge widths:
| Printer's unprintable edge | US Letter | A4 | ||
|---|---|---|---|---|
| Fit to page | Ten 1/4 in squares (63.5 mm) | Fit to page | Ten 5 mm squares (50 mm) | |
| 3 mm | 97.2% | 61.7 mm | 97.1% | 48.6 mm |
| 1/6 in (4.2 mm) | 96.1% | 61.0 mm | 96.0% | 48.0 mm |
| 5 mm | 95.4% | 60.6 mm | 95.2% | 47.6 mm |
| 1/4 in (6.35 mm) | 94.1% | 59.8 mm | 94.0% | 47.0 mm |
| Actual size / 100% | 100% | 63.5 mm | 100% | 50.0 mm |
So with Fit to page left on, a sheet always comes out between about 94% and 97% of its real size. That’s why our calibration wizard treats any measurement of 94 to 97 mm on its 100 mm bar as a print-dialog problem, not a printer one. The error also grows with distance, which is why it matters most on long things like rulers:
Settings by app and device
Chrome and Edge (Windows, Mac, Chromebook)
- Open the PDF and press Ctrl+P (Cmd+P on a Mac).
- Click More settings.
- Under Scale, choose Custom and type 100. Avoid Fit to paper and Fit to printable area.
- Check the Paper size matches the sheet you downloaded, Letter or A4.
Firefox
Press Ctrl+P, open More settings, and under Scale choose the percentage option and set it to 100 rather than fitting to the page width.
Safari and Preview (Mac)
- Press Cmd+P and click Show Details if the dialog is small.
- In the Preview section, choose Scale and set it to 100%, rather than Scale to Fit.
Adobe Acrobat and Acrobat Reader
- Press Ctrl+P or Cmd+P.
- Under Page Sizing & Handling, click Size and choose Actual size. Fit and Shrink oversized pages both scale.
Windows printer settings
Some printer drivers have their own resizing option under Printer Properties or Preferences, often called Fit to page, Scaling or Resizing options. Leave it at 100% or Normal; a driver setting can shrink the page even when the app says 100%.
iPhone, iPad and Android
Phones and tablets rarely offer a scale setting. Choose the Paper size that matches the sheet (Letter or A4), print, and measure. If the result is short, print the same file from a computer, or calibrate so the next download makes up the difference.
How to check your printout
Measure something with a known length, using a steel ruler if you can.
- On graph paper, measure across ten squares: ten 1/4 in squares should be 63.5 mm (2.5 in) and ten 5 mm squares 50 mm.
- On a ruler printout, check the 10 cm mark, or lay a bank card along it: cards in the ID-1 format are 85.6 mm wide.
- About 94 to 97% of the right length: the dialog is still scaling. Find the setting above and print again.
- Within about 0.5 mm over 100 mm: fine for every practical purpose.
- Off by less than 1%, or more in one direction than the other: that’s the printer itself. Calibrate.
When the printer itself is off
Even at 100%, paper feed rollers and print heads are not perfect. Most home printers land within about half a percent, but some print up to a percent large or small, often slightly differently across and down the page. You can’t fix that in the dialog, but you can make up for it in the file.
The calibration wizard prints this sheet, asks what you measured across and down, and saves a correction for that printer in your browser. Every PDF you download afterwards is adjusted inside the file, so the page size stays the same and the download button shows that calibration is on. The margin lines tell you the printer’s real unprintable edge, which is also the number to look up in the table above if you ever do need Fit to page.
