TrueOffset vs Prime Time NTP

TrueOffset is a precision time utility for comparing time sources and measuring clock offset with clarity and confidence. Compare multiple Network Time Protocol (NTP) servers, visualize the difference between them, and see how your device's clock aligns with selected references. A clean, instrument-style interface presents time as a measurement—focused on accuracy, not decoration. FOUR CLOCK FACES - 12-Hour Classic — Traditional analog display - 24-Hour Scientific — Full day on one dial - NTP Offset — Dual second hands show device vs. true time - Digital — Large display with millisecond precision UTC & TAI TIME SCALES Display Coordinated Universal Time (UTC) and International Atomic Time (TAI) alongside your local time. UTC and TAI feature authentic deadbeat second hands that step crisply to each second, visually distinct from the smooth-sweep local time. TAI runs 37 leap seconds ahead of UTC—see both atomic time scales at a glance. PRECISION VISUALIZATION The NTP Offset view displays two second hands: your device clock (gray) and true NTP time (green). The offset magnifier shows drift on a ±10ms scale, so you can see sub-millisecond accuracy at a glance. DUAL-STACK COMPARISON A feature no other NTP app offers: compare IPv4 and IPv6 paths to the same server. Detect DNS misconfigurations, identify when address families route to different servers, and verify your network is delivering consistent time on both stacks. FLEXIBLE TIME SOURCES Compare against Apple, Google, Cloudflare, NIST, US Naval Observatory, global NTP pools, or add your own servers. Set any source as your reference and track offsets across all configured servers. QUALITY ANALYTICS Eight swipeable chart pages reveal the character of your time sources: - Dashboard — Sparkline overview of all servers - Offset History — Track drift over time - Histogram — Offset distribution analysis - Box Plot — Compare consistency across servers - RTT Scatter — Correlate latency with offset - Clock Sources — Decode reference clocks (GPS, PPS, Rubidium, Cesium) - Dual-Stack — IPv4 vs IPv6 path comparison - Rankings — Servers scored by jitter and round-trip time TrueOffset is designed for users who care about how accurate their time really is—and want to see the difference, not just trust it. --- In appreciation of Emerald Sequoia's Emerald Time.

"Prime Time" is a high-precision time app that shows the true time, accurate to the millisecond. It queries multiple 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 1.2] • The complete four-timestamp NTP exchange. The time a server spends preparing its reply is now removed from the measured delay instead of being counted as network transit. • A clock filter. Each server keeps its last eight exchanges, and the one with the lowest synchronization distance is used — not simply the newest — so one congested query no longer drags the reading with it. • Best-source marking. A green double ring shows the server with the lowest estimated error. The device offset is measured from that server and quoted with its ± accuracy. • Wi-Fi and cellular awareness. The link in use is shown, and an optional warm-up avoids measuring a radio that has just woken from idle. • Two in-app help screens explaining every mark on the display, and the reasoning behind how often servers are queried. • Japanese interface when the device language is Japanese. [Free] • Real-time sync with up to 5 NTP servers • Millisecond display, refreshed up to 120 times a second on ProMotion screens • Offset and round-trip time per server, with sparkline history • Stratum and reference clock ID per server • Adaptive polling that eases off as a server proves steady [Pro — one-time purchase, no subscription] • Manual sync on demand • Keep the screen awake while the app is open • Up to 30 NTP servers monitored at once 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.