Comparison

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.

Head to head
About

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.

Highlights
  • Millisecond time display
  • Queries multiple NTP servers
  • Detailed sync accuracy
  • Network performance metrics
  • Adaptive polling
  • One-time Pro upgrade
Features
Read full description

"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.

About

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.

Highlights
  • Millisecond accurate clock display
  • Device offset status
  • Network latency and drift reports
  • Precision alarm
  • Timecode and markers
  • Widgets
  • Multiple clock themes
Features
Read full description

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

Prime Time NTP4 screens
Atomic Exact Time4 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

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.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard3 real differences · 7 level
Prime Time NTP versus Atomic Exact Time: the parameters behind the verdict, then further details
ParameterPrime Time NTPAtomic Exact Time
PriceFreeFree
Rating4.0 (1 ratings)4.0 (1 ratings)
Positive reviews100.0% of reviews—
Number of ratings11
Update frequencyEvery 6 weeksEvery 5 weeks — better
AdsNo — betterYes
In-app purchasesYesYes
MonetizationFreemiumFree with in-app purchases
DevicesiPhone, iPadiPhone, iPad, Mac, Apple TV — better
Requires iOS26.016.4 — better
Further details — not scored
Size11 MB56 MB
Age rating4+4+
DeveloperKentaro SaitoSUPER KIM KIMYA VE TEKSTIL SANAYI TICARET LIMITED SIRKETI

Customer experience

Prime Time NTP

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Atomic Exact Time

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

1 purchases

Prime Time NTP

One-time1
  • Pro Features$4.99
3 purchases

Atomic Exact Time

Subscriptions2
  • Atomic Exact Time Pro7 Days trial$2.991 Month
  • Pro Yearly$19.991 Year
One-time1
  • Atomic Exact Time Pro$2.99

Questions

Is Prime Time NTP free?
Prime Time NTP is free to download, with in-app purchases available.
Is Atomic Exact Time free?
Atomic Exact Time is free to download, with in-app purchases available.
Which has better reviews, Prime Time NTP or Atomic Exact Time?
Prime Time NTP and Atomic Exact Time are both rated 4.0 out of 5 on the App Store, from 1 and 1 ratings respectively.
Do Prime Time NTP or Atomic Exact Time have ads?
Atomic Exact Time shows ads; Prime Time NTP does not.
Which is updated more often, Prime Time NTP or Atomic Exact Time?
Prime Time NTP ships an update every 6 weeks, and Atomic Exact Time every 5 weeks. Most recently, Prime Time NTP was updated on November 5, 2026 and Atomic Exact Time on November 6, 2026.

Other comparisons