Atomic Clock PRO vs TrueOffset
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Atomic Clock PRO
Get the most accurate time from an official atomic clock server. This app automatically detects your time zone and allows custom backgrounds. Easily switch between digital and analog clock displays with a swipe.
- Exact time from atomic clock
- Automatic time zone recognition
- Customizable background images
- Digital and analog clock modes
- Optional sound alerts
- Color customization
Read full descriptionHide full description
Get accurate time on your iPhone and iPad by syncing with an official atomic clock time server. Download now for free! If you want exact time, a precise time reference, or an easy-to-read clock display, this app is designed for that. It automatically recognizes your time zone, lets you use one of your own photos as the background, and lets you switch between a digital display and a classic analog clock with a simple swipe. It is ideal as a personalized desk clock, a reliable travel companion, an everyday reference clock, or when you need exact time to set a mechanical watch accurately. Overview: - Accurate and precise time synced from an official atomic clock time server - Automatically recognizes your time zone and shows the current local time - Choose digital, analog, or combined analog and digital clock displays - Swipe to switch between clock displays - Resize the digital clock for a larger or smaller display - Includes time (hours, minutes, and seconds), date, and day of the week (optional) - Optional sound every second or every minute - Change clock and background colors - Use your own photos as background images - Choose atomic clock sync or your device's system clock - Option to keep the screen awake while the app is open - Works in portrait and landscape mode - For iPhone and iPad Helpful for: - A personalized desk clock at home or at work - Getting the correct local time while traveling - Setting a mechanical watch accurately - A clear reference clock when you want accurate, easy-to-read time PLEASE NOTE: You can switch between the analog and digital clock by swiping left or right across the clock. Disclaimer: Please note that whilst all reasonable care has been taken to make this application as accurate as possible we can not guarantee 100% accuracy. Standard Apple Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
TrueOffset
Read full descriptionHide 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. TIME SIGNALS Hear the true second. Optional pips are timed against your NTP reference, so the start of each one marks the real second, not your device's idea of it. Choose from six classic signals synthesized to their published pitch and timing: Six Pips (Greenwich Time Signal), WWV, WWVH, CHU, Jihō, and Moscow Six Pips. Sound them on the hour, every 15 minutes, or every minute. Bluetooth or AirPlay speaker running late? Measure its delay with the microphone and TrueOffset compensates. TRUEOFFSET MASTER CLOCK Our tribute to the U.S. Naval Observatory's telephone time service. A tick sounds every second while a voice announces your local time and then Universal Time, each ahead of a beep that lands on the true second. Prefer it quiet? Switch the voice off and keep the ticks. TrueOffset is not affiliated with the U.S. Naval Observatory. 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
Verdict
The clearest difference is in-app purchases: TrueOffset at none against Atomic Clock PRO's 2. TrueOffset also leads on ads (none vs shown) and review sentiment (100% vs 73%). Atomic Clock PRO's advantage is ratings volume (10K vs 7) and iOS requirement (15.6 vs 17.6). On price 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
Both are free to download. Atomic Clock PRO sells 2 in-app purchases, starting at $1.99 per month. TrueOffset asks for nothing beyond the download.
TrueOffset holds the better App Store score, 4.9 against 4.7. That said, the two scores are not equally well evidenced: Atomic Clock PRO has 10K ratings behind it against 7, so its average is the more settled of the two. Written reviews point the same way: 73% of Atomic Clock PRO's written reviews are positive against 100% of TrueOffset's.
Atomic Clock PRO ships an update every 3 months, TrueOffset every 3 weeks. The most recent releases landed on October 25, 2026 and October 24, 2026 respectively.
| Parameter | Atomic Clock PRO | TrueOffset |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (10K ratings) | 4.9 (7 ratings) — better |
| Positive reviews | 73.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 10K — better | 7 |
| Update frequency | Every 3 months | Every 3 weeks — better |
| Ads | Yes | No — better |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Apple TV |
| Requires iOS | 15.6 — better | 17.6 |
| Further details — not scored | ||
| Size | 6 MB | 2 MB |
| Age rating | 4+ | 4+ |
| Developer | Brachmann Online Marketing GmbH & Co. KG | Richard Bollar |
Customer experience
Atomic Clock PRO
TrueOffset
Bugs and requests
Atomic Clock PRO
Reported bugs
3 issues- Second hand occasionally runs in reverse
- Digital clock display cuts off on some devices
- Inconsistent behavior when switching between clock types
Requested features
3 requests- Customizable clock face options
- Ability to set widget on home screen
- Sync with system clock to automatically update time
TrueOffset
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Atomic Clock PRO
- Premium$1.991 Month
- Remove Ads$5.99
TrueOffset
No in-app purchases
Questions
Is Atomic Clock PRO free?
Is TrueOffset free?
Which has better reviews, Atomic Clock PRO or TrueOffset?
Do Atomic Clock PRO or TrueOffset have ads?
Which is updated more often, Atomic Clock PRO or TrueOffset?
Other comparisons















