Mouse Acceleration: When cm/360 Does Not Match Your Hand

Where the centimetre figure comes from

One count turns 0.022 × in-game sensitivity degrees. cm/360 = 41563.64 ÷ eDPI, and eDPI is DPI × in-game sensitivity. Settings labels it “cm / 360°” and keeps two decimals.

800 DPI × 1.0 is eDPI 800 and 51.95 cm. A half turn is half of that, 25.98 cm. Settings has no half-turn row. 800 × 2.0 is also 25.98 cm for a full turn. A fresh install defaults to sensitivity 2 and 800 DPI, so you see 25.98 until you change it, not 51.95.

The setup row rounds the same formula to one decimal: 51.95 is shown as “52.0 cm per 360°”, and 25.98 as “26.0”. Measure against the two decimals. The setup row only checks you are starting on that sensitivity.

A fixed pointer speed is not acceleration

Pointer speed is one scale. The calibration factor defaults to 1, the usual Windows 6th notch, and is clamped from 0.1 to 4. It stores one ratio of pixels per count.

Acceleration changes with speed, so the same hand distance can report two pointer distances. One ratio cannot fit both. Settings says calibration only estimates a fixed multiplier and cannot remove pointer acceleration. It does not change cm/360.

On Windows, uncheck “Enhance pointer precision” under Settings → Mouse → Additional mouse options → Pointer Options. macOS has no checkbox of that name. This site does not detect the system, so use the ruler either way. Mouse software may have its own acceleration switch. This site cannot see it and recommends no brand.

What 2D, 3D and calibration read

2D asks for an ordinary pointer lock, not raw input. The crosshair then moves by reported movement times the calibration factor, and it stops at the edge. Picture width is the equivalent field of view, 90° by default, a quarter of a turn. At 51.95 cm/360 that width is about 12.99 cm of hand movement; at the default 25.98 it is about 6.5 cm. A longer mark pins both speeds to the edge. Do not sweep 51.95 cm across the 2D screen.

All six home-page modes can switch View between “2D flat” and “3D first-person”: Static clicking, Dynamic flicking, Tracking, Micro-adjust, Reaction time and Recoil control. Only 3D requests raw input. If the browser accepts it, each count turns 0.022° × sensitivity, the calibration factor and system acceleration are skipped, and the view can turn a full circle. If the browser refuses, 3D uses an ordinary lock and acceleration can still apply. The page never says which lock you got. Until 3D locks, it tells you to click before the view will turn.

Settings calibration is an ordinary lock. It sums signed movement, so move one way only. Under 200 px it will not store a factor. Touch follows the finger. Use a mouse.

Slow swipe, fast swipe

Do not change DPI or sensitivity first. Check the pair you already use. The 10 cm figure below is 3149.6 counts only at 800 DPI with factor 1, about 3150 px on the calibration line. Another DPI is 10 ÷ 2.54 × your DPI.

1. Open Settings and write down cm / 360° to two decimals. To audit the formula, type 800 DPI and 1.0: it shows 51.95, and a half turn is 25.98 cm. Put your usual pair back afterwards.
2. Mark 10 cm on the pad. Slide it one way without lifting. At 800 DPI and factor 1, expect about 3150 px.
3. Open Mouse movement calibration and click Start. Slide the 10 cm slowly, press Space or Esc, and note the net pixels. Repeat clearly faster. Do each speed three times. If one speed’s three runs scatter, check the ruler first.
4. If each speed agrees with itself but the two speeds differ, reported movement depends on speed. Within about 5% is the same band as measuring a full turn by hand. Wider than that, do not edit sensitivity from the centimetre figure yet.
5. Open Static clicking on “2D flat”. Wait until the cursor disappears. Space and Esc pause a round and unlock, so do not use them as the calibration stop key. Use a shorter mark that never hits the edge, once slow and once fast. If the crosshair stops in different places, 2D is still on the ordinary lock.
6. Switch View to “3D first-person” and start again. The crosshair stays centred. Move your written cm/360 slowly and see if a stationary target returns near the crosshair; then move the same length quickly. Raw input makes those stops agree. The page does not tell you that it succeeded. If they still disagree, this 3D lock is the ordinary one.

Edit sensitivity only after the speeds agree

1. If they disagree, uncheck “Enhance pointer precision” and any acceleration switch in the mouse software, then repeat the two 10 cm calibration swipes. Do not change DPI, sensitivity or grip the same day. See Mouse sensitivity and DPI and sensitivity.
2. 2D disagrees and 3D agrees: 3D got raw input, 2D did not. Do not treat Settings centimetres as pad distance during 2D practice.
3. Both disagree: turn acceleration off and measure again. Do not compensate by editing DPI.
4. When both agree, play 60 seconds of Static clicking with 3 or 4 targets, then 60 seconds of Micro-adjust on Normal. A perfect hit is inside 25% of the radius. That shows whether you can stop. It is not a reason to change sensitivity today. See Common mistakes.

Turning acceleration off does not raise your hit rate by itself, and no centimetre figure is promised to suit you. It lets one hand distance turn a similar angle at both speeds, so the two decimals and the ruler describe the same movement.

Questions

Can I practise with acceleration on?

Yes. 2D still locks. You cannot match 51.95 or 25.98 to the ruler until the slow and fast swipes agree.

Does calibration remove acceleration?

No. It stores one factor from 1, clamped to 0.1–4. One factor cannot fit two speeds, and cm/360 stays the same.

Does 3D always skip acceleration?

No. Only a lock the browser accepted as raw input skips it. A refusal falls back, and the screen does not say which you have.

Is there a macOS checkbox with the same name?

No. Compare a slow 10 cm with a fast 10 cm. A missing label is not proof that speed leaves the movement alone.