Laptop Bag Size Guide: Will a 13, 14, 15.6 or 17-Inch Laptop Actually Fit?

The single most common reason a laptop bag gets returned is that it fits the screen but not the machine. A laptop is sold by the diagonal measurement of its display. A bag has to hold a three-dimensional object with a lid, a hinge, feet and a rubber bumper. Those two numbers are not the same measurement, and nobody tells you that at the point of buying.

Here is the short version: measure your laptop's width, depth and thickness in centimetres, add about 1 cm to each, and compare that with the internal dimensions listed on the bag's product page. If the page only gives you a screen size, treat it as a guide rather than a guarantee.

Why screen size is a poor guide

Two 15.6-inch laptops can differ by three centimetres in width and by more than double in thickness. A thin aluminium ultrabook and a gaming laptop with a cooling system are both "15.6-inch" machines. Only one of them slides into a slim padded bay without a fight.

Screen size also ignores the bezel. A modern 14-inch laptop with almost no border around the display can have the same body width as an older 13-inch machine with a thick bezel. Manufacturers have been shrinking bezels for a decade, which means the relationship between "inches" and "centimetres of bag" keeps drifting.

How to measure your laptop in ninety seconds

1. Close the lid. Every measurement below is of the closed machine.
2. Width — the long edge, left to right.
3. Depth — front edge to hinge.
4. Thickness — the tallest point, which is usually the hinge end, not the front.
5. Add 1 cm to each. That is the room a padded sleeve needs to take the machine without you forcing it.

If you carry a charger, a mouse and a cable pouch, add their thickness too. A bag rated for a 15.6-inch laptop that is full of accessories behaves like a bag one size smaller, because the padded bay has to compress to make room.

What a laptop bay actually needs

Padding is not decoration. Three things matter more than the number of millimetres of foam:

• A raised base. The bottom of the laptop compartment should sit above the bottom of the bag. When you put a bag down, the impact goes into the base of the bag — a suspended bay keeps the laptop out of that impact zone. This is the single most important feature and the one most often missing.
• A closure on the bay itself. A velcro strap or a zip, so the machine cannot slide out when the bag is tipped or the main zip is open.
• A snug fit. A laptop that slides around inside a too-large bay takes more damage than one held still, because it gains momentum before it hits anything.

Sleeve, bay, or both?

A padded bay inside a backpack is enough for daily commuting. A separate laptop sleeve earns its place in three situations: when you want to pull the laptop out and carry it alone into a meeting; when you move the machine between two different bags; and when the bag you love does not have a proper suspended bay, in which case a sleeve gives you one.

Using both is not overkill for anyone who commutes on a motorbike or a crowded bus. It is the cheapest insurance available for a machine that costs more than the bag.

The sizes people actually carry

• 13 to 14 inch. The commuter sweet spot. Most convertible backpacks that also work as a messenger are built around this size, which is why they stay slim enough to wear to a meeting.
• 15.6 inch. The most common size in Pakistan and the one most bags quote. Check the thickness figure especially — this is where gaming machines catch people out.
• 17 inch. Genuinely difficult. Very few bags take one properly, and the ones that do are large enough that you will notice on a bike. Measure before you buy, without exception.

Before you click buy

Read the internal dimensions on the product page, not the headline size. If the bag is going to carry a charger and a water bottle as well, look for those to be in separate pockets rather than loose against the laptop — a charger brick pressed against a screen for an hour a day is how screens develop pressure marks.

Every bag in the backpacks and laptop bags range is built around a padded laptop bay, and the dimensions are listed on each product page. If you are unsure whether your machine will fit, message us with the model name before you order — it takes a minute and saves a return.