How do I know whether my laptop will fit the bag?

Bag sizes are given in inches based on screen diagonal, but 15-inch laptops from different makers have different bodies. The reliable way is to measure your laptop's width, length and thickness in centimetres and compare against the bag's internal dimensions rather than the stated inches.

Backpack or shoulder bag for a laptop?

A backpack spreads the weight across both shoulders, so it is easier on your back for longer carries and heavier loads. A shoulder bag is more convenient when you take the laptop out often — moving between meetings, for example.

Are the bags waterproof?

Most are splash-resistant rather than waterproof: the fabric handles short rain, but zips and seams let water through. If you need real protection, look for a model with a roll-top or a separate rain cover.