About
Measure Speed. Honestly.
SpeedReflex is a collection of utilities built to answer one question: how fast? How fast your hands react to a signal, how fast you launch when lights extinguish, and how fast you are really moving in a car, bike, train or plane.
Plenty of sites offer speed or reflex tools. We wanted tools engineered with measurement rigor, zero telemetry, and respect for your device hardware.
What We Care About
Accuracy First
Timing starts on the painted frame, inputs use hardware timestamps, and GPS glitches are filtered rather than shown as record speeds.
Private by Default
No accounts and no tracking. Location is processed on your device and history stays in your browser.
Honest Numbers
When a figure is modelled — like our reaction-time percentiles — we say so, rather than inventing a leaderboard.
Fast Everywhere
Small pages, no heavy frameworks, and tools that work on a cheap phone on a train as well as a gaming PC.
What We Care About
How We Time Your Reactions
- Frame-synced start: Timers start on the exact display refresh frame the visual signal is painted.
- Hardware event timestamps: We read the operating system hardware timestamp on key-down or pointer-down.
- Anticipation filter: Responses before the signal or under 100 ms are disqualified as guesses.
- Unpredictable hold intervals: Random delays prevent rhythmic guessing.
- Honest percentiles: Modelled against verified population data.
What We Care About
How We Measure Your Speed
- Doppler satellite receiver velocity takes precedence over simple distance division.
- Strict accuracy gates filter out weak GPS signals and multipath reflections.
- Plausibility bounds discard impossible acceleration anomalies (e.g. exiting tunnels).
Contact & Feedback
Plenty of sites offer speed or reflex tools. We wanted tools engineered with measurement rigor, zero telemetry, and respect for your device hardware.
Ready When You Are.
Test your reflexes with frame accuracy right now.