ROF Counter: A Free Rate of Fire App for Your Phone
ROF Counter measures rate of fire and shot timing using nothing but your phone's microphone. Set the phone down, tap Record, and shoot. When the string ends, you get your cyclic rate in rounds per minute, split times, shot groups, and a shot count, with no shot timer to hold and no extra hardware.
How it works
The clock starts at the first detected shot, not when you tap Record, so the time it takes to set the phone down and get ready never skews the numbers. A one-off handling thump is ignored. After 7 seconds of quiet the run ends on its own, or you can tap Stop. The app then analyzes only the span where shooting happened and shows the most useful headline for that string: cyclic RPM for fast bursts, or string time and splits for slower fire.
You can also import an existing video or audio file and analyze it the same way.
What it measures
- Shot count for the string
- Cyclic rate of fire in rounds per minute (RPM)
- Split times between shots
- Shot groups and bursts
- A shot-by-shot timeline you can trim one shot at a time
Export and compare
Results export as a per-shot CSV, a JSON file, a shareable image, or the original WAV audio. The app also keeps summaries of your 20 most recent runs in the browser so you can compare two runs side by side.
Private by design
All audio analysis happens on your phone. Recordings are not uploaded, and there is no account, advertising, or analytics service. Saved run history contains summary numbers only, never audio or file names.
Install it to your home screen
ROF Counter is an installable web app. Open rof.folsominnovations.com and add it to your home screen: on iPhone, use Safari's Share menu and choose Add to Home Screen; on Android, use Chrome's Install option. After the first load it works offline, so it is ready at a range without signal.
A measurement aid, not a safety device
Echoes, nearby shooters, mechanical noise, and heavily compressed video audio can affect results. Use ROF Counter as a measurement aid and always follow normal firearm-safety procedures.