Comparison

World Timezone Calendar vs Rainfall Calculator

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

Head to head
About

World Timezone Calendar

Easily schedule meetings and events across different time zones. This app helps you find the perfect time for global coordination by comparing multiple time zones and integrating with your existing calendar. Plan ahead with future time views and share events that automatically adjust to recipients' local times.

Highlights
  • Cross-timezone scheduling
  • View calendar in multiple timezones
  • Time travel to plan ahead
  • Add unlimited timezones
  • Day/night indicators
  • Home screen widget
  • Global event sharing
Features
Read full description

Coordinate global meetings, calls, and events without the timezone math. Standard world clocks only tell you what time it is right now. World Calendar goes further: it’s a powerful timezone converter and international meeting planner that lets you look into the future to find the perfect time for everyone. Whether you are scheduling a global team sync, planning an international trip, or calling family overseas, World Calendar integrates directly with your iOS Calendar to make cross-timezone scheduling effortless. CROSS-TIMEZONE SCHEDULING Compare multiple timezones side-by-side to instantly pinpoint the ideal meeting time. Tap anywhere to set a target time, and tap twice to seamlessly create an event directly in your calendar. VIEW YOUR CALENDAR IN MULTIPLE TIMEZONES World Calendar displays your existing events across all your selected timezones. Create, edit, and share events with a single tap, ensuring your global schedule is always perfectly aligned. KEY FEATURES: • Time Travel: Scroll into the future to plan days, weeks, or months ahead. • No Limits: Add and compare as many timezones as you need. • Day/Night Indicators: Instantly see if your contact is awake or asleep. • Home Screen Widget: Check your favorite timezones at a glance without unlocking your device. • Watch Widget and App: Put your recently selected timezones on your wrist • Easy Search: Find locations by city name, timezone abbreviation (e.g., EST, GMT), or UTC offset. • Global Sharing: Send event invites to other users that automatically adapt to their local timezone. • DST Accuracy: Fully automatic adjustments for daylight saving time changes globally. • Nautical Time Zones: Full support for standard UTC offsets without DST adjustments. • Landscape View: Turn your device for a wider, comprehensive timeline view.

About

Rainfall Calculator

Calculate potential rainwater harvest volume and cost savings. This tool helps determine annual water collection capacity based on rainfall and roof area, recommending optimal tank sizes for efficient water storage. It also allows for cost-saving analysis by comparing harvested water to mains water prices.

Highlights
  • Instant rainwater calculation
  • Cost savings evaluation
  • Minimum tank size recommendation
  • Supports various input units
  • Formula references included
  • Results copyable to other apps
Features
Read full description

The Rainfall Calculator is a physics/math tool designed to help you determine how many liters/gallons of rainwater you can harvest per year, evaluate cost savings, and recommend the minimum tank size for water storage. Features: - Instant calculation. - Results can be copied to other apps. - Includes formula references. - Supports up to 16 decimal places. - Supports various units for each input. - Works seamlessly on both iPhone and iPad. - Lightweight, compact app optimized for everyday use. - Ad-free and built with privacy in mind. Rainwater Collection Calculator: - The catchment area is multiplied by the depth of rain that falls on it to give the total volume of water produced. - 1 millimeter of rain over 1 square meter of roof equals 1 liter of water. - Annual rainfall (in millimeters) x Roof surface area (in square meters) = Roof catchment capacity. - You can add the cost of mains or tap water per m³ to evaluate the annual cost savings if this rainwater is collected and used instead of drinking water. - The minimum tank size should store 33% of the "Annual Rainfall On Your Roof Area" as you will use the water while you are collecting it. The rain will collect in gutters that channel the water into downspouts and then into some sort of storage vessel. Rainwater collection systems can be as simple as collecting rain in a rain barrel or as elaborate as harvesting rainwater into large cisterns to supply your entire household demand. You can also collect rainwater for garden use. Plants prefer rainwater because it's naturally soft and free of chlorine and other chemicals. If drought is a problem where you live, collecting rainwater is a good way to handle watering restrictions. If you're on a municipal water system, you can save a considerable amount of money. Thank you for your support! Visit nitrio.com for more apps for your iOS devices.

Screenshots

World Timezone Calendar4 screens
Rainfall Calculator4 screens

Verdict

The call

The clearest difference is price: World Timezone Calendar at Free against Rainfall Calculator's $2.99. World Timezone Calendar also leads on update cadence (every 4 months vs every 29 months) and ratings volume (315 vs 1). Rainfall Calculator's advantage is in-app purchases (none vs 1) and ads (none vs shown). On rating 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

World Timezone Calendar is free to download; Rainfall Calculator costs $2.99 up front. World Timezone Calendar sells 1 one-off in-app purchase. Rainfall Calculator asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.9 for World Timezone Calendar against 5.0 for Rainfall Calculator. That said, the two scores are not equally well evidenced: World Timezone Calendar has 315 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

World Timezone Calendar ships an update every 4 months, Rainfall Calculator every 29 months. The most recent releases landed on October 26, 2026 and October 13, 2026 respectively.

Scorecard7 real differences · 3 level
World Timezone Calendar versus Rainfall Calculator: the parameters behind the verdict, then further details
ParameterWorld Timezone CalendarRainfall Calculator
PriceFree — better$2.99
Rating4.9 (315 ratings)5.0 (1 ratings) — better
Positive reviews76.0% of reviews—
Number of ratings315 — better1
Update frequencyEvery 4 months — betterEvery 29 months
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
DevicesiPhone, iPad, Mac, Apple Watch — betteriPhone, iPad, iPod
Requires iOS16.613 — better
Further details — not scored
Size19 MB1 MB
Age rating4+4+
DeveloperGeospike Pty LtdNitrio

Customer experience

World Timezone Calendar

All ratings295 ratings
Positive98.6%
Neutral0.7%
Negative0.7%
Written reviews50 reviews
Positive76.0%
Neutral10.0%
Negative14.0%

Rainfall Calculator

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

World Timezone Calendar

Reported bugs

7 issues
  • 🐛 Inappropriate ads in free version
  • 🐛 Widget settings not saved
  • 🐛 Cannot add new events with double tap
  • 🐛 Timezone abbreviations not displayed
  • 🐛 Search feature doesn't work
Show 2 more
  • 🐛 Crashes when adding a city
  • 🐛 Widget expansion settings not saved

Requested features

5 requests
  • Add more cities
  • Option to freeze time zones for comparison
  • Switch between 24-hour and AM/PM clock
  • Cleaner design with better calendar event integration
  • Ability to pick a specific date to view

Rainfall Calculator

Not enough reviews yet to summarise bugs or requests.

In-app purchases

1 purchases

World Timezone Calendar

One-time1
  • Remove Advertising$19.95
None

Rainfall Calculator

No in-app purchases

Questions

Is World Timezone Calendar free?
World Timezone Calendar is free to download, with in-app purchases available.
Is Rainfall Calculator free?
Rainfall Calculator costs $2.99, with no in-app purchases.
Which has better reviews, World Timezone Calendar or Rainfall Calculator?
Rainfall Calculator is rated higher. World Timezone Calendar averages 4.9 out of 5 from 315 ratings, while Rainfall Calculator averages 5.0 from 1 ratings.
Do World Timezone Calendar or Rainfall Calculator have ads?
World Timezone Calendar shows ads; Rainfall Calculator does not.
Which is updated more often, World Timezone Calendar or Rainfall Calculator?
World Timezone Calendar ships an update every 4 months, and Rainfall Calculator every 29 months. Most recently, World Timezone Calendar was updated on October 26, 2026 and Rainfall Calculator on October 13, 2026.

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