The precision time app for people who care about milliseconds. Compare NTP servers, visualize clock drift, and see UTC/TAI with deadbeat second hands.
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.
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In appreciation of Emerald Sequoia's Emerald Time.
I always used Emerald Time, but the developer stopped developing the app and removed it quite some time ago. About every 6 months I would check the app store in the hopes of finding a similar app. I was so happy when I found TrueOffset today. This app is very similar and works excellent, just what I was looking for. Thank you for bringing back this type of app. My thanks to the developer for an excellent app that performs well and is easy to use. Job well done!
Emerald Time successor?
esambo
Finally an app that comes close what Emerald Time did. I love the millisecond precision and all the insights, and allowing me to add additional servers. Nice UI too.The dual stack comparison doesn’t seem to work for me. It might also be interesting to have two (or more?) different categories of servers, smearing vs non-smearing, as it doesn’t make sense to have some of each, and depending on the use case, one might make more sense than the other.I would also love a feature (on the Clock page) that just selects the best server from my list, just like Emerald Time did, so that I can determine what the most accurate device offset is. I assume the “Device Clock Offset” is based on the currently selected server. It would be nice if I could switch that to the one with the best quality (and perhaps even see which server that was).I also wouldn’t mind paying a few dollars for additional features like that, as long as it’s reasonable and not a subscription.I also wonder if reading the exact millisecond offset on the Clock could be improved with a little dot going around the outside of the analog clock circling, with markers for every 2-10 millisecond, depending on the screen size.Thanks so much
NTP is dead! Long live NTP!
K. M. Peterson
I was one of those really saddened by the demise of Emerald Time, and I’m greatly appreciative of the developer for taking up the mantle. There is a lot of information here, and lots to figure out. The only thing I could possibly ask for: sound effects. Having multiple iOS devices with ~ms synchronization emitting a 1- or 5-second tone was a great tool for understanding how location differences could be “heard”. Again, my thanks!
Great App!
G77777777777777777!
Works perfectly! Thank you. I do ntp redirects in my environment was hoping it would help me know if it was my internal ntp or external that was the actual resolver. Not sure if there is a way.
- UTC & TAI time scales — Display Coordinated Universal Time and International Atomic Time with authentic deadbeat (stepping) second hands
- Dual-stack comparison — Compare IPv4 vs IPv6 paths to detect DNS misconfigurations (a feature no other NTP app offers)
- Quality rankings — Servers ranked by jitter and RTT with visual scoring
- Enhanced analytics — 8 swipeable chart pages: Dashboard, Offset History, Histogram, Distribution, RTT Scatter, Clock Sources, Dual-Stack, and Rankings
- Reference clock decoding — See what's driving each server: GPS, PPS, Rubidium, Cesium, or upstream NTP
- Native NTP implementation — Built on Network.framework, no third-party libraries
- UTC calculation fix — Correct timezone handling for all regions
Version 1.1
The developer, Richard Bollar, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Privacy practices may vary, for example, based on the features you use or your age. Learn More
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
Seller
Richard Bollar
Size
1.8 MB
Category
Utilities
Compatibility
Requires iOS 17.6 or later.
iPhone Requires iOS 17.6 or later.
iPad Requires iPadOS 17.6 or later.
Mac Requires macOS 14.6 or later and a Mac with Apple M1 chip or later.
