Simplex in printing means single-sided printing, where ink is applied to only one side of the paper. It’s the counterpart to duplex printing, which prints on both sides. If you’ve seen this term in a printer menu or on a spec sheet, that’s all it refers to: one side of the page gets printed, and the other stays blank.
Simplex vs. Duplex Printing
The distinction is straightforward. Simplex prints on one side of each sheet. Duplex prints on both sides. Most modern office printers support both modes, and many default to duplex to save paper. When you see “simplex” in your print settings, selecting it forces the printer to use only one side of each page.
In duplex mode, the printer feeds the paper through, prints the first side, then flips the sheet internally and runs it through again to print the second side. Simplex skips the flipping step entirely. The paper passes through once, gets printed on one face, and drops into the output tray.
How It Affects Print Speed
Simplex is generally faster on a per-page basis because the printer doesn’t need to flip and re-feed each sheet. For a single document, the difference is negligible. But across a large print job, the extra mechanical step in duplex mode adds up. Printer manufacturers measure and report speeds separately for simplex and duplex modes using standardized testing (ISO/IEC 24734), and the duplex number is always lower.
That said, if you’re printing a 20-page document and your goal is to get through the whole thing quickly, duplex can actually be more efficient overall. You’re producing the same content on half the sheets, so the total time from start to finish may be comparable even though each individual sheet takes longer.
When Simplex Makes More Sense
Duplex saves paper, but simplex is the better choice in several common situations:
- Single-page documents. Letters, invoices, memos, and one-off pages don’t benefit from double-sided printing.
- Labels and envelopes. These materials can’t be flipped and re-fed through a printer. Simplex is the only option.
- Thick cardstock or specialty paper. Heavier media often can’t pass through the duplex mechanism without jamming.
- Photos and presentation materials. When print quality on one side matters and you don’t want ink show-through from the reverse, single-sided printing gives a cleaner result.
- Quick, short print jobs. If speed matters more than paper savings, simplex avoids the extra processing time.
How to Switch Between Simplex and Duplex
On most computers, you’ll find this setting in the print dialog box. On a Mac, go to File > Print, then look for a “Double-sided” checkbox. If it’s checked, you’re in duplex mode. Uncheck it to print simplex. On Windows, the option typically appears under “Printer Properties” or “Preferences” within the print dialog, often labeled “Print on Both Sides” or “Duplex Printing.” Turning it off gives you simplex output.
Some workplaces set duplex as the default across all networked printers. If you need simplex for a specific job, you can override this in the print dialog without changing the system-wide setting. In some environments, like university computer labs, you may need to select a specific printer name or queue designated for single-sided output.
Paper Use and Cost
The most obvious trade-off between simplex and duplex is paper consumption. A 10-page document printed simplex uses 10 sheets. The same document printed duplex uses 5. For offices printing thousands of pages a month, defaulting to duplex cuts paper costs roughly in half. This is why many organizations configure duplex as the standard setting on shared printers.
For home users or small print jobs, the savings are minimal. If you’re printing a recipe or a shipping label, there’s no practical reason to worry about which mode you’re in. Simplex is the simpler, more intuitive option for everyday single-page tasks, and it’s what most home printers do by default.