Desk mat size calculator
This calculator turns your desk width, desk depth, keyboard width and mouse sensitivity into one mat footprint in centimetres and inches. It works out the mouse lane your cm/360 requires, adds the keyboard zone, snaps to a standard retail size, and tells you whether the result is a small, medium, extended or full desk mat.
Work out your mat footprint
Measure the desk with a tape. Leave the keyboard width field at 0 to use the default for the keyboard class you pick.
The recommendation is geometry, not a product pick. Compare any mat you are considering against the centimetre figures above, and check the thickness before you put a monitor stand on it.
About this tool and its limits
Purpose: to support one decision, from numbers you supply.
Not suitable for: any medical, legal, safety or warranty decision.
Method type: arithmetic on your inputs, or an editorial rule stated below. It is not a validated model.
Accountable publisher: the editorial desk of this store.
Method version: 1.0. Last checked: 2026-09-14.
The calculation runs in your browser. This tool's own code does not save or transmit your answers. Separate site analytics and other services are described in our privacy policy.
| Input | What it means | Accepted values |
|---|---|---|
| Desk width (cm) | Used directly in the calculation. | any number, default 140 |
| Desk depth (cm) | Used directly in the calculation. | any number, default 70 |
| Measured keyboard width (cm) | Used directly in the calculation. | any number, default 0 |
| Mouse DPI | Used directly in the calculation. | any number, default 800 |
| In-game sensitivity | Used directly in the calculation. | any number, default 1 |
| Keyboard size | Used directly in the calculation. | Full size, number pad (about 44 cm), Tenkeyless (about 36 cm), 60 or 65 percent (about 29 cm) |
| Engine yaw constant | Used directly in the calculation. | Source engine, 0.022 (CS2, Apex, TF2), Valorant, 0.07, Overwatch 2 and Call of Duty, 0.0066 |
Worked example
With the pre-filled values shown above, it returns:
| Headline result | NaN x NaN cm |
| In inches | NaN x NaN in |
| Mat class | small |
| Keyboard zone | 44 cm (class default) |
| Mouse lane this leaves | NaN cm |
| Lane your sensitivity needs | 26 cm for a half turn |
Calculation checks
| Case | Observed behaviour |
|---|---|
| Boundary input (highest accepted values) | 60 x 40 cm |
| Invalid input (zero values) | -3 x 18 cm |
These checks show the tool behaves as documented. They do not establish medical or scientific validity.
What this result cannot tell you. It is an estimate derived entirely from the numbers you enter, using the relationships described on this page. It does not measure your situation, it does not account for anything not listed as an input, and it cannot establish which product you should buy. Where the result matters for your health, safety, money or a warranty, treat it as a starting point and check it against the primary source linked at the bottom of this page.
Products and commercial interest. This store sells the products these guides discuss. Product data never changes a calculation. To report a problem, use the contact page and include this page's URL, the inputs you used and the result you expected.
How the calculation works
- Your fidelity and sensitivity give an eDPI: DPI multiplied by in-game sensitivity.
- eDPI and the engine yaw constant give cm per 360: (360 x 2.54) / (eDPI x yaw).
- The lane requirement is half of that, capped at 55 cm, because a half turn covers the widest flick most players make without lifting.
- The keyboard zone is the measured width, or the class default, plus 7 cm for hand clearance on the mouse side.
- The footprint is snapped up to the nearest standard width, then checked against the desk: nothing wider than desk width minus 3 cm, so the mat cannot overhang the front edge.
- Depth follows sensitivity: 25 cm for fast settings, 30 cm for the middle, 40 cm once cm/360 passes 40 cm.
Two more things this tool cannot see: whether your monitor stand base will sit on the mat, and whether your chair armrests clear the front edge. Both are physical checks worth doing with a tape before ordering.
Reading the result
| Output | What it means | What to do with it |
|---|---|---|
| Mouse lane this leaves | Free travel between the keyboard edge and the end of the mat | It should be at least the lane figure below it. If not, go one standard size up. |
| Lane your sensitivity needs | Half your cm/360 turn | This is a target, not a hard limit. Above 55 cm the returns flatten. |
| Mat class | Small, medium, extended or full desk | Use it to filter listings. Compare millimetres, not the label. |
| Nearest standard size | The retail footprint closest to what your setup needs | If it says none fits, the desk is the constraint. |
Use this with
- eDPI and sensitivity converter for the cm/360 figure on its own
- Desk mat size guide explains what to measure and how thickness affects a monitor stand
- Gaming desk setup checklist for the other five measurements
- How we research and test these guides
Sources
- Calculator Academy. cm per 360 calculator: formula, yaw values and worked examples — calculator.academy/cm-per-360-calculator
- Calculate.co.nz. eDPI calculator: eDPI = DPI x sensitivity, cm per 360 derivation — www.calculate.co.nz/edpi-calculator.php
- Corsair. Extended mouse pad size labels and dimensions used for the standard size list — www.corsair.com/us/en/c/mousepads/extended-mouse-pad
- OSHA. Computer Workstations eTool, monitors: viewing distance and desk space between the user and the monitor — www.osha.gov/etools/computer-workstations/components/monitors