Comparison

World Clock vs Hazard buster

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
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"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

Hazard buster

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HAZARD Busterは、スマートフォンに内蔵されたGPS(全地球測位システム)と世界地図を利用して、世界各地にいる出張者・駐在員の現在地情報を、地図上で一元的に表示・確認ができるサービスです。日本からの出張者が多い中国では、グーグルの使用が規制されているため、中国では百度マップを利用することで、世界中で利用いただけます。  また、出張者・駐在員はHAZARD Busterの報告機能を利用できます。例えば、テロや災害等の緊急時には出張者・駐在員が「安否確認」報告を送信することにより、管理者からも迅速で簡単に安否確認できます。  さらに、チャット機能、掲示板機能、特定のエリア内にいる出張者・駐在員に注意喚起などのメッセージを流せる機能も取り揃えています。  これまで、有事の際の出張者・駐在員の安否確認には、渡航情報と照らし合わせたり、現地法人と連絡を取り合ったり、アナログで対応することが多く、時間がかかっていましたが、HAZARD Busterでは、簡単に位置情報を確認でき、様々な手段で連絡が取り合えるように、新たな安否確認のニーズに対応しました。 本アプリケーションをご利用頂くには、ジョルダン株式会社が提供するHAZARD Busterのご契約いただく必要があります。 「暖かいヒント」 - Hazard Busterにて定期的に位置情報取得を有効にしていると、アプリに切り替え、バックグラウンドでアプリを実行し続ける事も出来ますが、アプリの消費電力が以前よりも多く、スマホのバッテリー寿命に影響を与えます - Hazard Busterにて(iOS版)最低バージョンがiOS11.4以上のサポートとなります - 位置情報がバックグラウンドでアプリを実行し続けると、スマホのバッテリー寿命に影響を与えます

Screenshots

World Clock4 screens
Hazard buster4 screens

Verdict

The call

The clearest difference is in-app purchases: Hazard buster at none against World Clock's 1. Hazard buster also leads on ads (none vs shown). World Clock's advantage is update cadence (every 6 weeks vs every 3 months). On price, device support and iOS requirement 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. Hazard buster asks for nothing beyond the download.

UpkeepUpdate frequency

World Clock ships an update every 6 weeks, Hazard buster every 3 months. The most recent releases landed on October 26, 2026 and October 9, 2026 respectively.

Scorecard3 real differences · 7 level
World Clock versus Hazard buster: the parameters behind the verdict, then further details
ParameterWorld ClockHazard buster
PriceFreeFree
Rating3.9 (14 ratings) — better—
Positive reviews77.4% of reviews—
Number of ratings14 — better—
Update frequencyEvery 6 weeks — betterEvery 3 months
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationAd-supported—
DevicesiPhone, iPodiPhone, iPod
Requires iOS15.014.0 — better
Further details — not scored
Size6 MB93 MB
Age rating4+4+
DeveloperYuki FukuiJ-FRONTIER CO.,LTD.

In-app purchases

1 purchases

World Clock

One-time1
  • Remove Advertisement$1.99
None

Hazard buster

No in-app purchases

Questions

Is World Clock free?
World Clock is free to download, with in-app purchases available.
Is Hazard buster free?
Hazard buster is free to download, with no in-app purchases.
Do World Clock or Hazard buster have ads?
World Clock shows ads; Hazard buster does not.
Which is updated more often, World Clock or Hazard buster?
World Clock ships an update every 6 weeks, and Hazard buster every 3 months. Most recently, World Clock was updated on October 26, 2026 and Hazard buster on October 9, 2026.

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