# sTEM controller vs Next Big Day

The clearest difference is in-app purchases: sTEM controller at none against Next Big Day's 1. Next Big Day's advantage is update cadence (every 2 weeks vs every 5 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Next Big Day sells 1 one-off in-app purchase. sTEM controller asks for nothing beyond the download.

sTEM controller ships an update every 5 months, Next Big Day every 2 weeks. The most recent releases landed on October 30, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | sTEM controller | Next Big Day |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/next-big-day-event-countdown/id6759345908/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 2 weeks** |
| Monetization | — | Free |
| Size | 29 MB | 24 MB |
| Requires iOS | **17.0** | 18.6 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [Temcompany ApS](https://appshunter.io/developer/1700820640) | [Gemsheer Chalil](https://appshunter.io/developer/1777244155) |

## What reviewers say

### sTEM controller

[App page](https://appshunter.io/ios/app/stem-controller/id6457210066)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Next Big Day

[App page](https://appshunter.io/ios/app/next-big-day-event-countdown/id6759345908)

Visualize your year with a unique dot matrix timeline and countdown to important events. Add tasks, notes, and photos to create rich memory journals. Share custom countdown images and sync with your Apple Calendar.

**Highlights:** Yearly dot matrix timeline visualization, Event countdowns for milestones, Home screen widgets, Event planning with tasks and notes, Rich memory journaling, Custom countdown image sharing, Apple Calendar sync

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lifetime Pro | $8.99 | one-time |


## Frequently asked questions

### Is sTEM controller free?

sTEM controller is free to download, with no in-app purchases.

### Is Next Big Day free?

Next Big Day is free to download, with in-app purchases available.

### Do sTEM controller or Next Big Day have ads?

Neither sTEM controller nor Next Big Day shows ads.

### Which is updated more often, sTEM controller or Next Big Day?

sTEM controller ships an update every 5 months, and Next Big Day every 2 weeks. Most recently, sTEM controller was updated on October 30, 2026 and Next Big Day on October 31, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*