Prime Time NTP

"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 1.3]
• Server details: tap any server to see everything about it: the address that actually answered, stratum, reference (with a reverse lookup of its name), any announced leap second, root delay and dispersion, server processing time, jitter, estimated error, and its last eight exchanges.
• Now in German and French, alongside English and Japanese.
• A new typeface for small text and figures. The large clock is unchanged.
• The Display Legend now explains the main screen's headings, including which way the offset sign points.
• A redesigned Pro screen.

[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 pulling the time shown.
• Manual sync on demand
• Keep the screen awake while the app is open

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, and anyone curious about how far off their device's clock really is.