Prime Time NTP vs Atomic Exact Time
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Prime Time NTP
This utility app displays the precise current time, accurate to the millisecond, by querying multiple NTP servers. It offers detailed insights into clock synchronization and network performance, with advanced features available via a one-time purchase.
- Millisecond time display
- Queries multiple NTP servers
- Detailed sync accuracy
- Network performance metrics
- Adaptive polling
- One-time Pro upgrade
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"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 1.4] • Display Offset (Pro): run the large clock up to 99.999 seconds ahead of or behind real time, in 1 ms steps — for remote broadcasts, live streams, or any delayed feed. While it is on, the time turns yellow, with the offset above and the actual time below, so there is no mistaking it for real time. Measurements are never shifted. • Server details now use two columns in landscape on iPhone, so everything fits on one screen. • On iPhone with ProMotion, the clock now refreshes up to 120 times a second. [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 skewing the time shown. • Manual sync on demand • Keep the screen awake while the app is open • Display Offset: run the clock ahead of or behind real time 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, broadcast crews, and anyone curious about how far off their device's clock really is. Available in English, Japanese, German, and French.
Atomic Exact Time
This app precisely calibrates your device's clock against internet time sources, accounting for network delays. It offers a full-screen display with millisecond accuracy, detailed reports on clock deviation, and a precision alarm. Ideal for professionals and enthusiasts requiring exact timing.
- Millisecond accurate clock display
- Device offset status
- Network latency and drift reports
- Precision alarm
- Timecode and markers
- Widgets
- Multiple clock themes
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See your device clock in context with Atomic Exact Time. Compare it with network time sources, view the measured offset and estimated uncertainty, and use a corrected clock display. Start with the free clock and synchronization tools. The free version includes ads. Optional Pro plans remove ads and unlock precision targets, team countdowns, detailed accuracy reports, Theme Studio, timecode and export tools. Prepare a start: choose an exact time or a duration, check calibration and notification permissions, and test the sound before starting. Save, edit, duplicate and reorder your frequent targets. Share a team target through a link or QR code. Each participant uses their own device calibration. Participant attendance and location are not tracked. Use world clocks, Studio Mode, accessibility preferences and a home-screen widget that shows the latest calibration. Choose from 15 interface languages. Timing accuracy depends on network conditions, device behavior and measurement quality. Uncertainty is an estimate, not a guarantee. Keep the app open for the best countdown timing. Background notification delivery depends on the operating system. Available Pro plans and localized prices are supplied by your store. Monthly and yearly subscriptions renew automatically until canceled in store account settings. A lifetime purchase is a single payment when offered. Restore Purchases is available. No app account is required. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is ads: Prime Time NTP at none against Atomic Exact Time's shown. Atomic Exact Time's advantage is device support (4 vs 2) and iOS requirement (16.4 vs 26.0). On price, rating, ratings volume and update cadence 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. Prime Time NTP sells 1 one-off in-app purchase and Atomic Exact Time sells 3 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 4.0 for Prime Time NTP against 4.0 for Atomic Exact Time. Both are backed by a comparable volume of ratings — 1 and 1 respectively.
Prime Time NTP ships an update every 6 weeks, Atomic Exact Time every 5 weeks. The most recent releases landed on November 5, 2026 and November 6, 2026 respectively.
| Parameter | Prime Time NTP | Atomic Exact Time |
|---|---|---|
| Price | Free | Free |
| Rating | 4.0 (1 ratings) | 4.0 (1 ratings) |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 1 | 1 |
| Update frequency | Every 6 weeks | Every 5 weeks — better |
| Ads | No — better | Yes |
| In-app purchases | Yes | Yes |
| Monetization | Freemium | Free with in-app purchases |
| Devices | iPhone, iPad | iPhone, iPad, Mac, Apple TV — better |
| Requires iOS | 26.0 | 16.4 — better |
| Further details — not scored | ||
| Size | 11 MB | 56 MB |
| Age rating | 4+ | 4+ |
| Developer | Kentaro Saito | SUPER KIM KIMYA VE TEKSTIL SANAYI TICARET LIMITED SIRKETI |
Customer experience
Prime Time NTP
Atomic Exact Time
In-app purchases
Prime Time NTP
- Pro Features$4.99
Atomic Exact Time
- Atomic Exact Time Pro7 Days trial$2.991 Month
- Pro Yearly$19.991 Year
- Atomic Exact Time Pro$2.99
Questions
Is Prime Time NTP free?
Is Atomic Exact Time free?
Which has better reviews, Prime Time NTP or Atomic Exact Time?
Do Prime Time NTP or Atomic Exact Time have ads?
Which is updated more often, Prime Time NTP or Atomic Exact Time?
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