Comparison

Datum vs DayNumCalc

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

Head to head
About

Datum

A minimalist calendar application designed for Apple devices, offering a clean interface and customizable widgets for iOS, macOS, and watchOS. View upcoming events, daily schedules, and monthly overviews directly from your home screen or watch face.

Highlights
  • Minimalist calendar interface
  • Lockscreen widgets for iOS
  • Event display widgets
  • Calendar widgets with event marks
  • watchOS calendar and complications
  • Support for iPhone, iPad, Mac, and Apple Watch
Features
Read full description

Datum is a minimalistic iOS, watchOS, macOS and visionOS calendar app. For iOS there are Lockscreen Widgets that show you the current date and there are Lockscreen Widgets that show up to 3 events for today. The iOS and macOS apps include the following widgets: - a small widget that shows the current date and at the bottom the events for this day - a small widget that shows a calendar with up to 3 event marks for each day - a medium widget that shows the same as the first small widget and on the right side a calendar with up to 3 event marks for each day - a large widget that shows the same as the medium widget and a list of the upcoming events - a extra large widget that shows a calendar and a list of the upcoming events (only for iPadOS 15+) The watchOS app shows a calendar with up to 3 event marks for each day. You can switch to the next/previous month by tapping on the arrows at the bottom of the calendar. You can view all events for each day by tapping on a day. There are also complications for all watchfaces included that show you the current date.

About

DayNumCalc

This utility app provides quick access to date calculations, including finding the day number for any date, determining a date from a day number, calculating the difference between two dates, and checking the day of the week. It also offers widgets for convenient access on your home and lock screens.

Highlights
  • Calculate day number from date
  • Determine date from day number
  • Calculate days between two dates
  • Add/subtract days from a date
  • Check day of the week
  • Home screen widgets
  • Today View widgets
  • Lock screen widgets
Read full description

DayNumCalc gives easy access to basic date calculations: - The current date/day number information is immediately available. Examples: day 1 = 1 January; day 365 = 31 December (non-leap year) or 30 December (leap year) - Date/day number calculations: get the day number from a chosen date, and a date from a paired year/day number - Calculate the number of days between two dates - Determine a date after adding or subtracting a number of days fro a chosen date - Check the day of the week for a date of your choice Widgets for the Home Screen, the Today View, and the Lock Screen are available for ease of use.

Screenshots

Datum3 screens
DayNumCalc4 screens

Verdict

The call

The clearest difference is update cadence: Datum at every 3 months against DayNumCalc's every 6 months. Datum also leads on device support (5 vs 3). DayNumCalc's advantage is price ($0.99 vs $1.99) and iOS requirement (15.5 vs 17.6). On review sentiment, ads, in-app purchases and monetization model 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

Datum costs $1.99 and DayNumCalc $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Datum ships an update every 3 months, DayNumCalc every 6 months. The most recent releases landed on September 7, 2026 and September 10, 2026 respectively.

Scorecard4 real differences · 6 level
Datum versus DayNumCalc: the parameters behind the verdict, then further details
ParameterDatumDayNumCalc
Price$1.99$0.99 — better
Rating—4.8 (6 ratings) — better
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings—6 — better
Update frequencyEvery 3 months — betterEvery 6 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhone, iPad, Mac, Apple Watch, Vision Pro — betteriPhone, iPad, iPod
Requires iOS17.615.5 — better
Further details — not scored
Size11 MB1 MB
Age rating4+4+
DeveloperMichael LindingerMayra M Martinez

Customer experience

Datum

Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

DayNumCalc

All ratings6 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews4 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Datum

No in-app purchases

None

DayNumCalc

No in-app purchases

Questions

Is Datum free?
Datum costs $1.99, with no in-app purchases.
Is DayNumCalc free?
DayNumCalc costs $0.99, with no in-app purchases.
Do Datum or DayNumCalc have ads?
Neither Datum nor DayNumCalc shows ads.
Which is updated more often, Datum or DayNumCalc?
Datum ships an update every 3 months, and DayNumCalc every 6 months. Most recently, Datum was updated on September 7, 2026 and DayNumCalc on September 10, 2026.

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