Displayed TC accuracy
-- ms
Browser clock offset
-- ms
Best RTT
-- ms
Median RTT
-- ms
Average RTT
-- ms
Offset jitter
-- ms
Backend NTP accuracy
-- ms
Browser-backend RTT
-- ms
Browser-backend jitter
-- ms
Browser vs backend
-- ms
Samples used
--
Display model
Browser
Browser corrected time
--:--:--.---
25 fps LTC
--:--:--:--
30 fps LTC
--:--:--:--
Accuracy by framerate
RTT and offset
Ready.
Measurement samples
| # | Used | RTT ms | Offset ms | t1 client send | t2 server receive | t3 server transmit | t4 client receive | Info |
|---|
What this can and cannot know
When hosted on a web server, this app first measures the backend server against NTP, then measures the visitor's browser against the backend with an NTP-like HTTP exchange. It cannot perfectly prove one-way network delay because the outbound and inbound paths may be asymmetric. Constant delay is less harmful than jitter and changing asymmetry, so the calculation uses many samples, rejects high-RTT outliers, and prefers the lowest-RTT measurements. The displayed timecode is therefore an estimate for this browser, limited by browser-to-server latency and jitter.