Comparison

World Clock vs Calkillator

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

Calkillator

Features
Read full description

All calculator apps are the same? THAT'S NOT TRUE —! Meet Calkillator — the calculator that understands your voice. Instead of tapping buttons one by one, simply say what you want to calculate. "Subtract 3,500 from 20,000." That's it. No typing. No complicated formulas. Just speak, and Calkillator does the math instantly. Key Features • Voice Calculation — Calculate naturally using your voice in Korean, English, Japanese, Chinese, Spanish, and Thai. • Natural Currency Questions — Just ask, "How much is 1 dollar in Korean won?" and Calkillator understands and converts instantly — no typing, no separate converter screen. • 5 Everyday Tools — Percentage, tip calculator, unit converter, BMI calculator, and currency converter, all built in. Try them free for 7 days. • Scientific Calculator Mode — Go beyond basic calculations with trigonometric functions, logarithms, exponents, roots, constants, parentheses, and more. • Powerful Expression Engine — Supports addition, subtraction, multiplication, division, parentheses, operator precedence, and complex mathematical expressions. • Export & Share History — Save your calculation history as a text file or share it instantly. • Clean Dark UI — Fast, simple, and distraction-free design optimized for everyday use. • Privacy First — No ads. No tracking SDKs. No data sent to servers. Built to Keep Getting Better Calkillator's voice recognition will continue to evolve. We're continuously improving the voice recognition engine to better understand natural expressions, different speaking styles, and real-world calculation scenarios — including everyday currency questions like "How much is that in dollars?" The calculator you buy today will keep getting smarter. Calkillator Minions (In-App Purchase – $0.99) Unlock Voice Input and all 5 everyday tools — plus PRO features — with a single one-time purchase. Pay once. Use forever.

Screenshots

World Clock4 screens
Calkillator4 screens

Verdict

The call

The clearest difference is ads: Calkillator at none against World Clock's shown. On price, update cadence, in-app purchases 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 and Calkillator sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

World Clock ships an update every 6 weeks, Calkillator monthly. The most recent releases landed on October 14, 2026 and October 3, 2026 respectively.

Scorecard1 real difference · 9 level
World Clock versus Calkillator: the parameters behind the verdict, then further details
ParameterWorld ClockCalkillator
PriceFreeFree
Rating3.9 (14 ratings) — better—
Positive reviews77.4% of reviews—
Number of ratings14 — better—
Update frequencyEvery 6 weeksMonthly — better
AdsYesNo — better
In-app purchasesYesYes
MonetizationAd-supported—
DevicesiPhone, iPod — betteriPhone
Requires iOS15.6 — better16.6
Further details — not scored
Size6 MB25 MB
Age rating4+4+
DeveloperYuki Fukui221B STUDIO

In-app purchases

1 purchases

World Clock

One-time1
  • Remove Advertisement$1.99
1 purchases

Calkillator

One-time1
  • Calkillator Minions$0.99

Questions

Is World Clock free?
World Clock is free to download, with in-app purchases available.
Is Calkillator free?
Calkillator is free to download, with in-app purchases available.
Do World Clock or Calkillator have ads?
World Clock shows ads; Calkillator does not.
Which is updated more often, World Clock or Calkillator?
World Clock ships an update every 6 weeks, and Calkillator monthly. Most recently, World Clock was updated on October 14, 2026 and Calkillator on October 3, 2026.

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