Article
Printer Margins: The Unprintable Area in Millimetres
Every printer refuses to ink a strip around the edge of the page. We size that strip from published spec sheets and calculate why it forces "fit to page" to shrink your document.
Print a document at “Fit to page” and it comes out looking fine — smaller than you specified, but fine. Print the same file at “Actual size” and something stranger happens: the dialog may warn that part of the page falls outside the printable area, or the driver quietly clips it. Neither is a bug. Both trace back to a physical fact about the printer on your desk: it cannot put ink anywhere near the edge of the sheet.
Our printing guide already covers what to click — Actual size instead of Fit, which paper size to load, how to run a calibration test. This article covers what that guide only states as a rule: why the unprintable strip exists, how big it actually is on real printers, and how it produces the 3–7% shrink figure we mention in why we built dynamic generators instead of static PDFs.
What a spec sheet means by “unprintable area”
Every printer has a rectangle, smaller than the paper itself, where it is mechanically capable of placing ink or toner. Manufacturers document this as an “unprintable area” or “non-printable margin,” expressed as a distance from each of the four edges. Anything your document places outside that inset rectangle is either clipped by the printer or has to be scaled down before it gets there — there is no third option.
This is a real, published spec, not a marketing footnote. HP, Canon, Epson, and Brother all list minimum margins for specific models in their support documentation and printer manuals, and the numbers differ meaningfully between models, between inkjet and laser mechanisms, and even between edges of the same page.
Why the edges are off-limits: grip, feed, and overspray
The unprintable area is not a firmware limitation invented to annoy you. It comes from two physical constraints:
- The paper has to be held while it moves. A sheet travels through the print zone gripped by rollers on at least one edge at any given moment. The print head or laser drum cannot deposit anything reliably in the strip where a roller — or the mechanical structure holding it — physically occupies the paper path.
- Ink cannot be trusted at the exact edge. On an inkjet, spraying droplets right up to the paper boundary risks overspray past the sheet and onto the machine’s internal platen, which then transfers stray ink to the next page. Keeping a small buffer from the true edge avoids that.
Laser printers face a related but distinct version of the same problem: toner has to fuse under heat and pressure rollers that also need to grip an edge of the sheet, and the transfer drum has geometric limits on how close to true zero it can place a charge.
Why the bottom edge loses more than the top
If you compare published margins across models, one pattern shows up repeatedly on inkjets: the bottom margin is often two to six times larger than the top, left, or right margin. This is not arbitrary — it comes directly from how the sheet is grabbed as it exits.
Inkjet printers hold the sheet in the print zone with a pinch roller pressing the paper against a drive roller. Manufacturer patent filings on inkjet paper-handling mechanisms describe the constraint explicitly: once the trailing edge passes the last pinch-roller contact line, nothing holds the paper flat and in registration, so placement becomes unreliable. The fix is to stop printing before that point — the minimum bottom margin is set by the distance from the print head’s last usable position to that roller line, not an arbitrary safety buffer. The top, left, and right edges don’t share this problem, because the sheet stays under roller control while they pass through the print zone. That is why, on the HP and Epson rows below, the bottom figure dwarfs the other three.
Published margins for five printer families
The table lists minimum unprintable-area figures stated in each manufacturer’s own documentation for that model or series, on A4 paper unless noted. We did not test these printers — every figure is quoted or directly derived from the cited page.
| Printer family | Type | Top | Bottom | Left | Right | Source |
|---|---|---|---|---|---|---|
| HP Deskjet 920c / 940c / 948c series | Inkjet | 1.8 mm | 11.7 mm | 3.4 mm | 3.4 mm | HP’s published minimum printing margins for these Deskjet series |
| Canon PIXMA PRO-200 | Inkjet | 3.0 mm | 5.0 mm | 3.4 mm | 3.4 mm | Canon’s official specifications page for the PIXMA PRO-200 |
| Epson Stylus Pro 7800 / 9800 | Inkjet (large-format, cut sheet) | 3.0 mm | 14.0 mm | 0 mm* | 0 mm* | Epson’s official printer specification documentation for the Stylus Pro 7800/9800 |
| Brother HL-2070N | Mono laser | 4.23 mm | 4.23 mm | 6.01 mm | 6.01 mm | Brother’s official support FAQ for the HL-2070N (portrait A4) |
| Brother HL-4570CDW | Color laser | 4.23 mm | 4.23 mm | 4.23 mm | 4.23 mm | Brother’s official support FAQ for the HL-4570CDW (A4/Letter) |
*The Stylus Pro 7800/9800’s zero left/right figure applies to its borderless-capable cut-sheet handling; it is a large-format proofing printer, not a typical home inkjet, and is included to show how far the range extends.
Notice the pattern isn’t even uniform within one manufacturer’s laser lineup: the HL-2070N publishes a larger side margin than top/bottom, while the newer HL-4570CDW publishes 4.23 mm on all four edges. Margins are a property of a specific model’s paper path, not a fixed constant for “laser” or “inkjet” as categories.
The arithmetic: from a hardware margin to a fit-to-page percentage
This is arithmetic on the published numbers above, not a measurement of any print job. Take an A4 page (210 × 297 mm) with content designed edge-to-edge, and work out what scale a driver’s “Fit to page” would need to shrink it to clear each printer’s printable rectangle in both dimensions — then keep the smaller (limiting) of the two, since Fit to page preserves aspect ratio:
| Printer family | Width-limited scale | Height-limited scale | Fit-to-page uses | Net shrink |
|---|---|---|---|---|
| HP Deskjet 920c series | 96.8% | 95.5% | 95.5% (height) | 4.5% |
| Canon PIXMA PRO-200 | 96.8% | 97.3% | 96.8% (width) | 3.2% |
| Brother HL-2070N | 94.3% | 97.2% | 94.3% (width) | 5.7% |
| Brother HL-4570CDW | 96.0% | 97.2% | 96.0% (width) | 4.0% |
Every one of these four lands between 3.2% and 5.7% — squarely inside the 3–7% shrink range we cite elsewhere on this site. That’s not a coincidence; it’s the direct, computable consequence of the hardware margins each manufacturer already publishes. A “Fit to page” driver isn’t picking an arbitrary shrink percentage — it is solving exactly this equation for whichever printer it’s talking to. This is a separate mechanism from the A4-versus-Letter mismatch, which produces its own, larger shrink or clip when the PDF’s page size doesn’t match the paper in the tray; unprintable-margin shrink happens even when the paper size is correct.
Borderless printing doesn’t remove the margin — it hides it by enlarging
Given a hardware margin that can’t be inked, “borderless” printing looks like the obvious fix: no white edge, ink goes all the way to the paper boundary. It works, but not by expanding what the printer can physically reach. Instead, the driver enlarges your content beyond 100% — commonly around 2% per edge in the simplest automatic implementations, though the figure and whether it’s adjustable varies by brand: some Epson drivers expose the expansion amount directly, Canon offers a choice between scaling to a target size or accepting overspray at actual size, and HP typically applies it automatically with little user control. The oversized image prints past the true paper edge, and the overspray lands in an internal collection sponge rather than on the sheet.
That enlargement is the opposite problem from a hardware margin. A margin makes your content too big for the printable rectangle, so the driver shrinks it. Borderless mode makes your content bigger still, on purpose, so there’s no white sliver at the edge. Either way, whatever left your printer at “100%” did not print at 100%. For anything you intend to measure afterward — a grid on graph paper, a length on a ring sizer, a spacing guide on printable paper generally — borderless mode is not a workaround for the margin problem. It’s a different, uncorrelated distortion stacked on top of it.
How much margin to leave, and what can ignore all of this
Given the spread in the table above — bottom margins from 4.2 mm to 14 mm, side margins from 3.4 mm to 6 mm — a practical safe zone for anything you design to be printed is roughly 13–15 mm (about half an inch) clear of every edge, with a little extra at the bottom if you don’t know which printer it will land on. That comfortably clears every figure we found published, the large-format Epson outlier included.
Two categories of content can mostly ignore this article:
- Anything read or filled in rather than measured — a coloring page, a chore chart, a certificate, a crossword. A shrink of a few percent or a clipped millimeter at one edge changes nothing about whether the page still does its job.
- Anything trimmed after printing at a professional shop, which uses bleed and trim lines rather than a consumer printer’s unprintable-area logic entirely.
Everything else — grids, rulers, sewing patterns, planner inserts meant to align with a punch, name-tracing letter heights — is exactly the content our printing guide tells you to print at Actual size and verify with a ruler, for precisely the reasons worked out above.
What we can’t tell you from a spec sheet
Manufacturers do not publish these figures consistently. Some list per-edge margins directly, as Brother does in the FAQ pages cited above; others publish only an overall “printable area” size per format and leave you to subtract it yourself. Specialty media makes it worse: Canon’s documentation notes a 35 mm top-and-bottom margin for certain fine-art papers on some large-format models — nearly ten times the plain-paper figure from the same manufacturer. Figures can also differ between regions, between a manual feed tray and a cassette on the same model, and between driver versions released years apart. Read this as “printers in general have a margin this size, sourced from real documentation, and that’s why the driver has to shrink your page” rather than “your printer has exactly this margin.” The only way to know your printer’s actual figure is the calibration test in our printing guide: print a known length at 100% with borderless and Fit both switched off, then measure it.