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Version 1.4 • Display Offset (Pro): run the large clock up to 99.999 seconds ahead of or behind real time, in 1 ms steps — for remote broadcasts, live streams, and other delayed feeds. While it is on, the time turns yellow, with the offset above and the actual time below. Measurements are never shifted. • Server details: two columns in landscape on iPhone, so everything fits on one screen. • On iPhone with ProMotion, the clock now refreshes up to 120 times a second. Requires iOS 26 or later.
"Prime Time" is a high-precision time app that shows the true time, accurate to the millisecond. It queries NTP servers directly — the same infrastructure that keeps the internet in sync — and works out the correct time from their answers. Your device's own clock is never used for the display. [New in version 1.4] • Display Offset (Pro): run the large clock up to 99.999 seconds ahead of or behind real time, in 1 ms steps — for remote broadcasts, live streams, or any delayed feed. While it is on, the time turns yellow, with the offset above and the actual time below, so there is no mistaking it for real time. Measurements are never shifted. • Server details now use two columns in landscape on iPhone, so everything fits on one screen. • On iPhone with ProMotion, the clock now refreshes up to 120 times a second. [Free — one server, in full detail] • Real-time sync with one NTP server of your choice • Every exchange laid open: address, stratum, reference, root delay, jitter, estimated error, and the last eight exchanges • Millisecond display, refreshed up to 120 times a second on ProMotion screens • Offset and round-trip time with sparkline history • Adaptive polling that eases off as a server proves steady [Pro — one-time purchase, no subscription] • Compare up to 30 servers. With three or more, a server that is off is outvoted instead of skewing the time shown. • Manual sync on demand • Keep the screen awake while the app is open • Display Offset: run the clock ahead of or behind real time A note on accuracy: a round trip is a single number covering two unknown halves, and nothing in the exchange reveals how it was divided. Prime Time widens the reported ± rather than inventing a correction to hide it. On cellular, where the two directions are least alike, that margin is wider — and shown. Made for developers, network engineers, broadcast crews, and anyone curious about how far off their device's clock really is. Available in English, Japanese, German, and French.