Comparison

AtomicClock vs TrueOffset

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

AtomicClock

This app displays the exact current time synchronized with NTP servers, offering a customizable clock view for precise time checks. It's ideal for setting watches, verifying timestamps, or comparing local and network time.

Highlights
  • Precise time from NTP servers
  • Customizable clock faces
  • Select or add time servers
  • Local and UTC views
  • 12/24 hour modes
  • Customizable time format
  • Acoustic ticking
Features
Read full description

Check precise NTP reference time at a glance. AtomicClock helps you set watches, wall clocks, cameras, and other devices, compare local time with UTC, and follow moments when every second matters. Clear analog and digital time AtomicClock displays current time from NTP servers that reference atomic clocks. Choose a predefined server or add your own, then view local or UTC time in a clean analog or digital clock. Customize your reference clock • Switch between 12-hour and 24-hour time • Customize the time format • Choose from multiple clock faces and hands • Use a smooth, fluid second hand • Add acoustic ticking or the Greenwich Time Signal • Tap the screen to hide information and controls, freeze the display, or mute ticking Details for precise time checks View technical NTP information, including round-trip time and server stratum. Whether you are checking a timestamp, preparing a camera, aligning a wall clock, or setting a watch by hand, the seconds remain clear and easy to follow. AtomicClock is free to use. AtomicClock Pro is available as a one-time purchase with no subscription. It unlocks your preferred clock face, hands, and font, removes ads, and includes upcoming Pro features. AtomicClock displays NTP reference time for comparison and does not change your device’s system time. Results can vary with the selected server, network conditions, and device behavior.

About

TrueOffset

Features
Read full description

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.

Screenshots

AtomicClock4 screens
TrueOffset4 screens

Verdict

The call

The clearest difference is in-app purchases: TrueOffset at none against AtomicClock's 1. TrueOffset also leads on ads (none vs shown). AtomicClock's advantage is iOS requirement (15.0 vs 17.6). On price, update cadence and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. AtomicClock sells 1 one-off in-app purchase. TrueOffset asks for nothing beyond the download.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 3 weeks. The most recent releases landed on October 2, 2026 and September 20, 2026 respectively.

Scorecard3 real differences · 7 level
AtomicClock versus TrueOffset: the parameters behind the verdict, then further details
ParameterAtomicClockTrueOffset
PriceFreeFree
Rating4.8 (5.5K ratings) — better—
Positive reviews84.2% of reviews—
Number of ratings5.5K — better—
Update frequencyEvery 3 weeksEvery 3 weeks
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, iPodiPhone, iPad, Apple TV
Requires iOS15.0 — better17.6
Further details — not scored
Size17 MB2 MB
Age rating4+4+
DeveloperTimo PartlRichard Bollar

Bugs and requests

AtomicClock

Reported bugs

3 issues
  • Crashes on certain iOS versions
  • Occasional freezing of hands
  • Countdown timer sound not working

Requested features

5 requests
  • Add GMT/dual time display
  • Implement widget support
  • Add different second hand sounds
  • Allow setting background color to match watch
  • Include alarm/timer functionality

TrueOffset

Not enough reviews yet to summarise bugs or requests.

In-app purchases

1 purchases

AtomicClock

One-time1
  • Lifetime Pro Version$6.99
None

TrueOffset

No in-app purchases

Questions

Is AtomicClock free?
AtomicClock is free to download, with in-app purchases available.
Is TrueOffset free?
TrueOffset is free to download, with no in-app purchases.
Do AtomicClock or TrueOffset have ads?
AtomicClock shows ads; TrueOffset does not.
Which is updated more often, AtomicClock or TrueOffset?
AtomicClock ships an update every 3 weeks, and TrueOffset every 3 weeks. Most recently, AtomicClock was updated on October 2, 2026 and TrueOffset on September 20, 2026.

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