Mouse pad sizes: which one do you need?
There is no standard mouse pad size: each maker names its own. A classic pad is about 34 to 36 cm wide, a large one about 45 cm, and an XL desk mat 90 cm or more, wide enough for the keyboard too. Choose by how far you move the mouse: the pad has to hold your longest sweep plus the mouse itself.
How wide does your pad need to be?
These are example values: type your own over them.
Every pad in the chart below is wide enough.
Half of 40 cm, plus 6.5 cm for the mouse = 26.5 cm.
This counts the sweep from one side of the pad to the other. If you rest the mouse in the middle and turn either way, you need a half turn's room on both sides: choose the full turn.
Don't know your cm/360? A ruler finds it in a few minutes: measure your turn by hand.
Mouse pad sizes compared
Real sizes from the makers' own pages, narrowest first. The names are not a standard: Razer's Medium is wider than Logitech's classic G240, and Logitech's Large is a centimetre wider than Razer's.
The line marks the width you need: 26.5 cm (10.4 in).
Low or high sensitivity
The lower your sensitivity, the further you move the mouse for each turn, and the wider the pad you need. At 25 cm a full turn, even a full turn fits on a classic pad; at 60 cm, a half turn with a 6.5 cm mouse already needs 36.5 cm, wider than both classic pads here. Changing your DPI or in-game sensitivity changes your cm/360, so check the width again after a change.
Depth: room to move up and down
Most aiming is sideways, so depth matters less than width. A deeper pad keeps your wrist and forearm on the same surface as the mouse: the classic pads here are 27.5 to 28 cm deep, the large ones 40 cm.
XL desk mats: measure your desk first
An XL pad, 90 to 94 cm wide, goes under the keyboard too, so the mouse never runs off an edge in the middle of a sweep. Measure the free width of your desk before you buy one: Razer's 3XL is 120 cm wide and 55 cm deep.
To choose your DPI, see the best DPI for gaming; to check what your mouse really sends, use the mouse DPI test; to compare your setting with other players', use the eDPI calculator.
Sizes from the makers' product pages: Logitech G240, G640 and G840; Razer Gigantus V2; Corsair MM300 PRO Extended.