Most "improve your reaction time" advice is fantasy — your raw nervous-system speed barely moves. What does move is the slack: the milliseconds you lose to a cold start, a slow monitor, a bad night's sleep, and a tense hand. Tick the conditions that apply to you below and this tool estimates your realistic recoverable ms and a trained target. It is brutally honest: if you already do everything right, it will tell you there is almost nothing left to gain.
The numbers here are midpoints of well-documented ranges from reaction-time research, not promises. They tell you where your slack is, so you fix the biggest source first instead of grinding a reaction-test trainer that gives almost nothing back. Everything runs locally in your browser.
0–5 ms recoverable. That is correct. At that point your number is your number, and the way to "win faster" is anticipation, not reflex training.Each factor contributes an evidence-based ms range and the tool sums the midpoints:
| Factor | Typical recovery | Why |
|---|---|---|
| Warm up before playing | ~15–30 ms (mid 22) | Cold-start reaction time is reliably slower; a few minutes of clicking closes most of it. |
| 60Hz → 144Hz+ monitor | ~20–40 ms (mid 30) | Pure display latency between you and the stimulus; included in your measured score. |
| Fix sleep / fatigue | ~20–50 ms (mid 30) | Sleep loss inflates simple reaction time and lapses substantially. |
| Moderate caffeine | ~5–12 ms (mid 8) | Tightens speed and reduces lapses for most people at a sensible dose. |
| Relaxed hand / posture | ~3–8 ms (mid 5) | A relaxed, slightly bent finger fires faster and more consistently than a tense extended one. |
Factors are not perfectly additive in reality — some overlap — so treat the total as an optimistic ceiling. Even so, fixing the top one or two sources is where almost all of your gain lives.
Simple visual reaction time is gated by neural conduction: light hits the retina, a signal travels to the visual cortex, a decision forms, and a motor command runs down to your finger. That pipeline is roughly 180–220 ms in a healthy adult and it does not meaningfully shrink with practice — you cannot train your axons to conduct faster. What changes is everything around the pipeline: are you warmed up, is your hardware adding delay, are you alert. That is the slack this tool measures.
So when an aim-trainer or app promises to "boost your reaction time," be skeptical of anything beyond removing slack. The honest version of reaction training is: warm up, sleep, fix your monitor, relax your hand — then stop chasing the reaction number and go train the things with real headroom. We break that down in how to improve reflexes.
Raw reaction time is mostly fixed, but recoverable slack is real: ~15–30 ms warmup, ~20–40 ms monitor, ~20–50 ms sleep, a few ms caffeine/posture. Most people reclaim 20–60 ms total, not more.
Yes — about 20 to 40 ms of display latency versus 60 Hz on the same person. It removes hardware delay, not neural delay, but your measured score includes it.
A moderate dose ~30 min before play tightens speed and consistency by a few to ~10 ms and reduces lapses. Too much causes jitter. It cannot fully replace sleep.
Small returns once slack is removed. The bigger wins are anticipation and crosshair placement, which reduce how fast you must react at all.