Methodology – How Our Measurements Work

By Musab Mehmood, Founder & Editor · Last updated: October 8, 2026

This page documents exactly how DPI Analyzer Pro measures, calculates, and validates — written like a lab note, limitations included. If a number on this site matters to you, this is where you check our work.

1. How the pointer-lock DPI measurement works

A browser cannot read your mouse's hardware DPI setting — there is no web API for the sensor's CPI register. What it can do is measure mouse movement precisely using the Pointer Lock API, which reports raw movementX/movementY deltas in device pixels, bypassing the OS cursor and screen edges.

The procedure:

1. The tool requests pointer lock on a target area. You move the mouse a known physical distance — typically measured against an on-screen ruler or a physical reference you provide (e.g., moving the mouse exactly 10 cm across your pad).
2. During the movement, the tool sums the raw movement deltas reported by the browser.
3. Estimated DPI = total reported counts ÷ physical distance in inches.
4. The measurement repeats over multiple trials; the tool reports the mean, and the deviation mode reports spread statistics (see §4).

What this actually measures: the effective counts-per-inch your operating system delivers to applications — which is hardware DPI modified by any OS-level scaling, driver settings, or mouse software profiles. If your Windows pointer speed isn't 6/11 or your mouse software applies a DPI shift, the estimate reflects the effective value, not the sensor's native step. That's the honest number for gaming purposes, and the tool says so on the page.

2. Formulas

All calculators on this site use these exact formulas:

• eDPI = DPI × in-game sensitivity
  Example: 800 DPI × 0.4 (Valorant) = 320 eDPI.
• cm/360 = (360 ÷ (yaw × sens × DPI)) × 2.54
  where yaw is the game's degrees of rotation per mouse count at sensitivity 1. Example: Valorant at 800 DPI, 0.5 sens, yaw 0.07 → (360 ÷ 28) × 2.54 = 32.66 cm.
• Sensitivity converter (game A → game B):
  target_sens = source_sens × source_yaw × source_DPI ÷ (target_yaw × target_DPI)
  This matches cm/360 exactly between games — the only conversion that preserves muscle memory.

For Fortnite, the in-game slider is a percentage, so the yaw is expressed per 1% slider unit (see table below) and sensitivity enters the formula as the slider value (e.g., 6.4).

3. Per-game yaw values (with sources)

Yaw = degrees of in-game rotation per mouse count at sensitivity 1. Every value below was verified against at least two independent sources:

Cross-check: Valorant's published constant cm/360 = 13,063 ÷ eDPI (Turbosmurfs.gg) matches our formula exactly: 360 ÷ 0.07 × 2.54 = 13,062.9. The CS2 sanity case (400 DPI × 2.0 sens) gives 51.95 cm — the widely published ~52 cm figure for that classic setup.

Known community discrepancy: some Fortnite sources use 0.5715°/count at 100% sens rather than our 0.5555°/count (0.005555 × 100) — a ~3% spread. It shifts cm/360 figures by the same ~3% and doesn't change any ranking or recommendation. We use 0.005555 per 1% for consistency with the majority of converter implementations.

Scoped/ADS sensitivities, FOV scaling, and per-weapon multipliers are not covered by hipfire yaw values; the converter matches hipfire cm/360 only.

4. Error bounds and what affects accuracy

The DPI estimate's accuracy depends on factors outside the tool's control. In practice, with careful technique, estimates land within ±5% of the effective DPI; sloppy technique can push error past ±15%.

• Physical distance measurement. The #1 error source. A 5 mm error on a 100 mm swipe is a 5% DPI error. Use a ruler, move in a straight line, and do multiple trials.
• Surface and sensor. Dirty pads, reflective spots, or lift-off during the swipe add noise. The deviation mode exists to catch this.
• Polling rate. At 125 Hz, fast swipes can under-report counts between polls. 500 Hz+ is recommended for measurement; the tool's polling-rate estimator tells you where you stand.
• OS/driver scaling. Windows pointer speed ≠ 6/11, "enhance pointer precision," or vendor DPI-shift profiles change the effective counts. The tool measures what games receive, which is what matters — but it won't match the number printed on your mouse box if scaling is active.
• Pointer-lock availability. Some browsers (notably mobile Safari and in-app webviews) don't support pointer lock. The tools detect this and say so rather than producing a fake number. A physical mouse is required — touchpads and touchscreens can't be measured meaningfully.

5. How deviation mode works

The DPI deviation test runs N repeated trials of the same physical movement and reports:

• Per-trial DPI — each swipe's estimate, so you can spot outliers.
• Mean — the average across trials; more stable than any single swipe.
• Standard deviation and CV% (coefficient of variation) — how spread out the trials are, relative to the mean.
• Plain-English verdict — "consistent" (low CV%: your sensor and technique are stable) vs. "check your sensor/surface" (high CV%: something is adding noise — dirty pad, lift-off, low polling rate, or a struggling sensor).

As a rule of thumb: CV% under ~3% is excellent, 3–7% is normal for hand-done swipes, and above ~10% means fix the setup before trusting the number.

6. Polling-rate estimator limitations

Browsers cannot read USB HID polling rate — no web API exposes it. The polling-rate test estimates it indirectly: it records the timestamps of mousemove events over a fixed window while you move the mouse continuously, then computes the effective report rate from the intervals.

Honest limitations:

• It's an estimate of the effective event rate, not a USB descriptor readout. Browser throttling, background tabs, and display refresh can all quantize the observed intervals.
• It can distinguish 125 vs 500 vs 1000 Hz reliably during vigorous movement, but 4000/8000 Hz mice will typically read as "~1000+ Hz" because the browser's event pipeline caps out first.
• The page labels the result "estimated" and explains this — any site claiming to read your exact USB polling rate in a browser is overstating.

7. Validation approach

• Formula spot-checks against hand-computed values and published community constants (the 13,063 Valorant constant, the ~52 cm CS2 reference setup) — all match.
• Yaw values verified against ≥2 independent sources each (table in §3); where the community disagrees (Fortnite), we document the spread.
• Pro-settings tables cross-checked against ≥2 independent databases per row where possible; rows that can't be corroborated are dropped, and source dates are published.
• Mouse DPI database specs taken from manufacturer pages only; a model is omitted if its native steps can't be confirmed.
• No fake precision: every tool output that depends on browser measurement is labeled "estimated," and pages state the browser limitations in plain language.

Found an error? Tell us — corrections are applied promptly and this page's date updates with them.