Time Difference Calculator

"An event in Mountain View next month starts at 10:00 AM local time. What time should I tune in from Japan?"

Have you ever found yourself in a situation like this?
While your smartphone's built-in clock app can show current times across different time zones, it doesn't allow you to change the time to a specific point in the future or past to see what the corresponding time would be.

That’s exactly why I created “Time Difference Calculator” (時差計算).
This is a world clock app focused entirely on simplicity, allowing you to intuitively check the time difference between overseas cities and Japan at a single glance.
There are no confusing settings or complex features. Just open the app, and you’ll instantly know the "now"—and even the future—of the city you're looking for.

This app was built entirely from scratch using "vibe coding." As someone with no prior coding experience, one of my main goals in releasing this app was to see how far a complete beginner could go on their own (well, with a big helping hand from Gemini!).

💡 Key Features & Characteristics

1) Intuitive Time Difference Display
Beautifully displays the current time of your registered cities in a clean list. You no longer have to do the mental math to figure out time differences.

2) Simple & Lightweight Design
By narrowing down the features to only what is absolutely necessary, the app opens and runs incredibly smoothly. It won't hog your device's storage. It also works offline, making it perfect to use during flights.


🌍 Recommended Situations

1) Planning and Traveling for Overseas Trips or Business
Perfect for checking the time the moment you land, or when you want to get in touch with family or colleagues back home.

2) Global Business Scenes
Quickly grasp meeting times with overseas clients or the operating hours of international branches. It's also great for tracking online global events and conferences.

3) Staying in Touch with Long-Distance Family and Friends
Helps maintain smooth communication tailored to the daily rhythms of your loved ones living abroad.


🛡️ Commitment to Safety & Security

To ensure a safe experience for all users, this app does not collect, transmit externally, or acquire any personal information or location data. With no ads and no unnecessary background data communication, anyone can use it safely and cleanly.