Comparison

Onetime. vs Zen World Time Converter

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

Head to head
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.

About

Zen World Time Converter

Easily find the current time in any location worldwide. This app simplifies scheduling calls across different time zones with an intuitive slider for quick time adjustments. It offers extensive location data and clear visual differentiation of day and night hours.

Highlights
  • Global time zone conversion
  • Over 22,000 locations
  • Customizable daylight hours
  • Intuitive time slider
  • Clear day/night differentiation
  • Ad-free experience
Features
Read full description

Zen World Time makes finding times in any location around the globe fast and easy. Figuring out the best time to call someone in a different time zone has never been easier—just drag our unique slider. Features • Over 22,000 locations available worldwide • Customizable daylight hours for each location • Elegant and intuitive interface • Nighttime and daytime hours are clearly differentiated • Time slider lets you advance to future times quickly • Ad-free • In-app purchase gives you access to all features Try it today!

Screenshots

Onetime.4 screens
Zen World Time Converter4 screens

Verdict

The call

The clearest difference is rating: Zen World Time Converter at 4.6 against Onetime.'s 3.3. Zen World Time Converter also leads on review sentiment (88% vs 51%) and update cadence (every 2 months vs every 11 months). Onetime.'s advantage is in-app purchases (none vs 1). On price, ads 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. Zen World Time Converter sells 1 one-off in-app purchase. Onetime. asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Zen World Time Converter holds the better App Store score, 4.6 against 3.3. Both are backed by a comparable volume of ratings — 42 and 189 respectively. Written reviews point the same way: 51% of Onetime.'s written reviews are positive against 88% of Zen World Time Converter's.

UpkeepUpdate frequency

Onetime. ships an update every 11 months, Zen World Time Converter every 2 months. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.

Scorecard7 real differences · 3 level
Onetime. versus Zen World Time Converter: the parameters behind the verdict, then further details
ParameterOnetime.Zen World Time Converter
PriceFreeFree
Rating3.3 (42 ratings)4.6 (189 ratings) — better
Positive reviews51.5% of reviews88.2% of reviews — better
Number of ratings42189 — better
Update frequencyEvery 11 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFreemium
DevicesiPhone, iPodiPhone, iPod
Requires iOS13.010.0 — better
Further details — not scored
Size2 MB18 MB
Age rating4+4+
DeveloperFLUID Design GmbHVlad Paraschiv

Customer experience

Onetime.

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

Zen World Time Converter

All ratings188 ratings
Positive88.8%
Neutral4.8%
Negative6.4%
Written reviews136 reviews
Positive88.2%
Neutral4.4%
Negative7.4%

User reviews

Onetime.

From 42 App Store ratings

What we love

  • ✨ Beautiful and elegant design
  • 👍 Intuitive and easy to use interface
  • 🌍 Great for visualizing time differences
  • 💡 Unique and innovative visualization
  • ✅ Works well for scheduling

Room to improve

  • 🐛 Data quality issues (incorrect times)
  • 🐛 Inability to add cities
  • 🐛 App crashes or freezes
  • 🐛 City search not working
  • 🐛 Some cities not recognized

Zen World Time Converter

From 189 App Store ratings

What we love

  • 👍 Simple and intuitive user interface
  • 🎨 Clean, elegant, and visually appealing design
  • ⚡ Easy to use for quick time zone comparisons
  • 🌍 Supports multiple cities simultaneously
  • 🔄 Smooth slider functionality for time adjustments

Room to improve

  • 🐛 Incorrect time zone data for some locations
  • 📱 Not optimized for iPad (iPhone-only formatting)
  • 🔒 Limited free version (only 2 cities)
  • 📊 Limited time range (only 7 days ahead)
  • 🎚️ Excessive scrolling needed to view all cities

Bugs and 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

Zen World Time Converter

Reported bugs

8 issues
  • Time doesn't auto-update after app launch
  • Red button to snap back to current time shows outdated time
  • Incorrect time zone placement (St. Barthélemy in French Alps instead of Caribbean)
  • Calendar functionality not working as expected
  • Sunrise/sunset can only be set in 30-minute increments
Show 3 more
  • Daylight saving time not captured correctly in some regions
  • Hijri calendar mode cannot be changed to Gregorian
  • Cannot select specific dates manually

Requested features

16 requests
  • 24-hour time format option
  • Ability to rearrange cities by drag-and-drop
  • Alphabetical or custom sorting of city list
  • Customizable font colors per city
  • Custom city names (e.g., 'Grandma', 'Corporate')
Show 11 more
  • Minute-level time interval adjustments (15-min, 1-min increments)
  • Quick date selection for future dates
  • Automatic sunrise/sunset time updates based on location
  • UTC time zone display
  • Compact view option to fit more cities on screen
  • Widget functionality for home screen
  • Outlook calendar integration
  • Ability to view previous days
  • Add missing cities and locations
  • Move app settings from iPhone settings into app
  • Zoom in/out functionality

In-app purchases

None

Onetime.

No in-app purchases

1 purchases

Zen World Time Converter

One-time1
  • Zen World Time Pro Features$5.99

Questions

Is Onetime. free?
Onetime. is free to download, with no in-app purchases.
Is Zen World Time Converter free?
Zen World Time Converter is free to download, with in-app purchases available.
Which has better reviews, Onetime. or Zen World Time Converter?
Zen World Time Converter is rated higher. Onetime. averages 3.3 out of 5 from 42 ratings, while Zen World Time Converter averages 4.6 from 189 ratings.
Do Onetime. or Zen World Time Converter have ads?
Neither Onetime. nor Zen World Time Converter shows ads.
Which is updated more often, Onetime. or Zen World Time Converter?
Onetime. ships an update every 11 months, and Zen World Time Converter every 2 months. Most recently, Onetime. was updated on October 24, 2026 and Zen World Time Converter on October 25, 2026.

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