# refreshratetest.app — full summary

> Free, private, browser-based refresh rate test. Measures display Hz, frame time, jitter, FPS spread, dropped frames and frame-pacing stability in 10 seconds, with a frame-time graph and a motion test. https://refreshratetest.app

## What it is

Refresh rate is how many times per second a display draws a new image, measured in hertz (Hz). 60Hz means a new frame every 16.7 ms; 120Hz every 8.3 ms; 144Hz every 6.9 ms; 240Hz every 4.2 ms. refreshratetest.app reports the rate a display is actually running at right now — which can differ from the number on the box because of OS settings, cables, drivers, or power-saving modes.

## How the measurement works

1. Browsers schedule animation with requestAnimationFrame, synchronised to the display's vertical refresh (V-Sync). The gap between two callbacks is one refresh period.
2. The test starts automatically when the page loads (and again whenever the user presses Test again, R, or the header "Run test" button).
3. It samples for 10 seconds. The first 0.4 seconds are skipped as warm-up; intervals longer than 250 ms are discarded as stalls.
4. Refresh rate = 1000 / median frame interval. The median resists occasional hitches that would drag an average down.
5. The raw value (e.g. 143.98Hz) snaps to the nearest standard rate if within 3% (→ 144Hz); otherwise it is rounded to the nearest whole Hz.
6. If the tab becomes hidden during a run, that run is discarded and restarts when visible, because hidden tabs are throttled.
7. After 10 seconds the result locks. Live readouts, the graph, and the motion test keep running so users can watch pacing change.

## Readouts

- Detected refresh rate (snapped Hz, plus raw measured Hz and a class label: Standard 60Hz, Smooth 75–100Hz, High refresh 120–144Hz, Gaming 165–200Hz, Esports 240Hz+)
- Current FPS (last ~0.5 s), Average FPS, Min / Max FPS
- Frame time (median, ms)
- Jitter (standard deviation of frame times, ms)
- Dropped frames (intervals ≥ 1.5× the median)
- Stability rating: share of frames within 10% of the median — Excellent ≥95%, Good ≥85%, Fair ≥65%, Unstable below
- Frame-time graph: lime bars for on-time frames, red bars for dropped frames, dashed line at the median
- Motion test: a saucer moving at 1×, 2× or 4× of 240 px/s with px/frame and px/s readouts; high refresh rates keep its edges crisp, dropped frames appear as visible jumps

## Controls

- Desktop: R retests anywhere; Space or Enter retests while the panel is focused; 1 / 2 / 3 set motion speed; M toggles sound; F toggles full screen
- Mobile and desktop: on-screen Start test / Test again button, 1× / 2× / 4× speed buttons, mute button, Clear saved results
- Header "Run test" button on any page scrolls to the test and starts a run without reloading

## Sound

Short synthesized Web Audio cues (start sweep, one-second ticks, completion chime, new-best arpeggio). No audio files. Mute persists between visits.

## Saved data

Stored only in the browser's localStorage under a versioned key: sound on/off, motion speed, number of tests, best refresh rate, and the last eight results (snapped Hz, raw Hz, average FPS, frame time, jitter, dropped frames, stability, timestamp). Nothing is uploaded; there is no account.

## Why a result may be lower than expected

- OS still set to 60Hz (Windows: Settings → System → Display → Advanced display; macOS: System Settings → Displays → Refresh Rate)
- Cable or port limits (use DisplayPort or certified HDMI 2.0/2.1, plugged into the graphics card)
- Power saving (laptops on battery, phone low-power modes, adaptive/ProMotion displays)
- Browser capping frames (hardware acceleration off, unfocused window, battery saver) — a ~30Hz reading is usually a power cap
- Multi-monitor: the browser syncs to the screen the window is on

## Limits

- A browser cannot see the full variable-refresh (G-SYNC/FreeSync) range; it normally reports the panel's maximum rate.
- Results reflect the browser's presentation rate on the current screen, not GPU rendering performance in games.

## Accessibility

All controls have explicit labels; canvases have descriptive labels; each completed result is announced via a polite live region; everything is keyboard operable; the dark theme meets WCAG AA contrast.

## Facts

- Name: Refresh Rate Test
- URL: https://refreshratetest.app
- Price: Free
- Platform: Modern desktop and mobile browsers
- Account: Not required
- Contact: malam169@gmail.com