About this tool
Work out keyboard height, keyboard tilt and how far your keyboard pushes the mouse out of a neutral reach.
The Keyboard and Mouse Position Guide measures three things that decide whether typing is neutral: the height of the key surface against your seated elbow height, the tilt of the key plane calculated from its front and back heights, and how far your keyboard's width pushes the mouse outside your shoulder line. Elbow height, forearm reach and shoulder width are derived from your body height using 50th-percentile adult proportions, and the mouse offset is compared against the reach the forearm covers on its own. It is aimed at anyone who has fixed the chair and the monitor and still has an aching mouse shoulder.
Open Keyboard and Mouse Position Guide on AltFTool — it loads instantly in your browser.
Enter your height in cm, seat height floor to cushion and desk height floor to surface; elbow height, forearm reach and shoulder width are derived from those.
Pick a Keyboard layout — Full-size 104 key at 44 cm, Tenkeyless 87 key at 36 cm, 75%, 65%, 60% or laptop — then give the mouse width, the gap to the mouse, the key heights at the front and back edges and the keyboard depth.
Read the mouse offset from your shoulder line, the keyboard tilt in degrees with a warning when it passes the neutral-wrist limit, and the table of where each layout would put the mouse.
Shows in centimetres how far each layout pushes the mouse outside the shoulder line — usually about 8 cm for a full-size board.
Keyboard tilt is calculated from the front and back key heights and its depth, not guessed from a picture.
Checks the mouse against the forearm-only reach zone scaled to your height rather than a fixed number.
Both at seated elbow height, with the mouse immediately beside the keyboard so it sits close to your shoulder line rather than out beyond it. For a 175 cm person on a 45 cm seat, elbow height is about 68 cm — well below the 73 to 75 cm most fixed desks are built at, which is why a tray or a raised chair with a footrest is so often needed.
Down, in almost every case. Raising the back feet tilts the key plane towards you and your wrists extend by roughly the same angle just to reach the keys. A flat or slightly negative tilt keeps the wrist closer to neutral, which is what OSHA and ISO 9241 describe as a straight wrist.
Yes, measurably. A full-size board is about 44 cm wide, so with a 7 cm mouse and a 2 cm gap the mouse centre sits 27.5 cm from your midline — roughly 7 cm outside the shoulder line for a 175 cm person. A tenkeyless board cuts that to about 3 cm and a 60% board to almost nothing.
As close as you can put it without hitting the keyboard — every centimetre of gap moves the mouse further from your shoulder. If you need the number pad, a separate numpad placed on your other side keeps the mouse in close while still giving you the keys.