Comparison

World Clock vs Onetime.

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

Head to head
About

World Clock

Easily calculate time differences worldwide by scrolling a dynamic time bar. Add any city, set specific dates and times, and plan international meetings or calls effortlessly. The app syncs with iOS time data.

Highlights
  • Dynamic time bar for instant difference calculation
  • Add and manage multiple cities
  • Direct date and time specification
  • Customizable city names
  • Syncs with iOS time data
Features
Read full description

"World Clock" is the best app to calculate time differences all over the world. All cities' times change automatically just by scrolling it with your finger. Therefore, you don't need to add or subtract times any more to calculate time differences. ■■Features■■ -Scrolling the time bar on the side of the screen up and down simultaneously changes the time in each city to the future or past. -Double-tap the time bar to change the time unit between 1 minute and 1 hour. -You can add any city from the list of cities provided in the app. -Tap each city to specify the date and time directly. -Press and hold on a city to change the city and edit the custom name. -Only one fixed city can be displayed at the top of the screen. ■■Examples of use■■ -International meeting planner -International call -Trip planning Disclaimer:This application has been built with extreme care and attention. However, it does not guarantee the accuracy of the names and times of the cities displayed. Please note that we are not liable whatsoever for any profit loss, or any other form of loss experienced by the customer from using this application. ※We don't have any time difference data in our app. We have been inquiring about time differences of each city to iOS. Therefore, “World Clock” shows you the time of iOS. As a result, depending on the version of iOS you are using, the exact time may not be displayed. If you find a time lag in our app, please confirm default "Clock" app on your iPhone. If the time in "Clock" app is the same with the time in our “World Clock”, it means that our app is running normally. ※Abbreviated name of time zone was originally researched and added. If you notice any mistakes, please contact us from the support site. ※The screenshots are specially edited not to show ads.

About

Onetime.

Visualize multiple world time zones on a single, intuitive dial. This app simplifies international scheduling and communication by displaying cities as they move through day and night, automatically handling daylight saving changes. Effortlessly find the perfect time for calls or to connect with loved ones globally.

Highlights
  • Single, easy-to-read time zone dial
  • Visualizes cities moving through day and night
  • Automatic daylight saving time adjustments
  • Timetravel™ feature for scheduling
  • Shareable time invites
Features
Read full description

One world. Onetime. Finally, a world clock that integrates all time zones into one easy-to-read dial. We are all living and working globally more and more, so we needed a way to simply see the time in cities around the world at a glance. That’s how Onetime was born. Built on the metaphor of the earth’s rotation, Onetime displays all the cities that matter to you as they move through the day and night in a natural, clockwise direction referencing the international date line. Whether you are scheduling an international call or checking to see what time it is back home, Onetime is the clock for you. No more mistakes adding and subtracting hours, no more confusing GMT numbers, no more remembering daylight savings calendars. Onetime takes care of it all, automatically. And with Timetravel™, you can fly through time so that you quickly find the right moment to schedule that important teleconference with your international colleagues or catch your loved ones before their bedtimes. The „Share“ feature lets you choose a date with TimeTravel and send an invite via message or email. Give up your wall of newsroom clocks and switch to Onetime today. Onetime. By FLUID. ABOUT FLUID Onetime was created by the award-winning design firm FLUID. With our locations in Munich and Silicon Valley and our international client base, the FLUID team is a heavy Onetime user, too.

Screenshots

World Clock4 screens
Onetime.4 screens

Verdict

The call

The clearest difference is in-app purchases: Onetime. at none against World Clock's 1. Onetime. also leads on ads (none vs shown) and iOS requirement (13.0 vs 15.6). World Clock's advantage is rating (3.9 vs 3.5) and update cadence (every 6 weeks vs every 11 months). On price, ratings volume 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. World Clock sells 1 one-off in-app purchase. Onetime. asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

World Clock holds the better App Store score, 3.9 against 3.5. Both are backed by a comparable volume of ratings — 14 and 39 respectively. Written reviews point the same way: 77% of World Clock's written reviews are positive against 51% of Onetime.'s.

UpkeepUpdate frequency

World Clock ships an update every 6 weeks, Onetime. every 11 months. The most recent releases landed on June 9, 2026 and September 17, 2026 respectively.

Scorecard7 real differences · 3 level
World Clock versus Onetime.: the parameters behind the verdict, then further details
ParameterWorld ClockOnetime.
PriceFreeFree
Rating3.9 (14 ratings) — better3.5 (39 ratings)
Positive reviews77.4% of reviews — better51.5% of reviews
Number of ratings1439 — better
Update frequencyEvery 6 weeks — betterEvery 11 months
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationAd-supportedFree — better
DevicesiPhone, iPodiPhone, iPod
Requires iOS15.613.0 — better
Further details — not scored
Size6 MB2 MB
Age rating4+4+
DeveloperYuki FukuiFLUID Design GmbH

Customer experience

World Clock

All ratings13 ratings
Positive76.9%
Neutral0.0%
Negative23.1%
Written reviews62 reviews
Positive77.4%
Neutral6.5%
Negative16.1%

Onetime.

All ratings39 ratings
Positive59.0%
Neutral2.6%
Negative38.5%
Written reviews134 reviews
Positive51.5%
Neutral5.2%
Negative43.3%

Bugs and requests

World Clock

Not enough reviews yet to summarise bugs or requests.

Onetime.

Reported bugs

8 issues
  • Incorrect time zone data for some cities (e.g., Taipei, São Paulo)
  • App freezes when trying to add cities
  • City search function not working ('No cities found')
  • App crashes on launch after updates
  • Time travel feature stops working with certain cities
Show 3 more
  • Scrolling back and forth in time no longer possible
  • App not working with latest iOS versions
  • Default 'My Time' zone cannot be removed

Requested features

9 requests
  • Ability to add descriptive labels for cities
  • Ability to add GMT/UTC time
  • Ability to add time zones manually
  • Homescreen widgets
  • Ability to toggle cities instead of removing
Show 4 more
  • iPad version
  • Tutorial on first launch
  • Option to reverse view horizontally
  • Ability to search future dates

In-app purchases

1 purchases

World Clock

One-time1
  • Remove Advertisement$1.99
None

Onetime.

No in-app purchases

Questions

Is World Clock free?
World Clock is free to download, with in-app purchases available.
Is Onetime. free?
Onetime. is free to download, with no in-app purchases.
Which has better reviews, World Clock or Onetime.?
World Clock is rated higher. World Clock averages 3.9 out of 5 from 14 ratings, while Onetime. averages 3.5 from 39 ratings.
Do World Clock or Onetime. have ads?
World Clock shows ads; Onetime. does not.
Which is updated more often, World Clock or Onetime.?
World Clock ships an update every 6 weeks, and Onetime. every 11 months. Most recently, World Clock was updated on June 9, 2026 and Onetime. on September 17, 2026.

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