# FLEX Study App vs 15

FLEX Study App and 15 are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

FLEX Study App ships an update every 5 months, 15 every 3 months. The most recent releases landed on May 16, 2026 and May 17, 2026 respectively.

## The numbers

| Metric | FLEX Study App | 15 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 3 months** |
| Size | 149 MB | 66 MB |
| Requires iOS | 12.0 | 12.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 12+ |
| Developer | [Definitive Media Corp.](https://appshunter.io/developer/996237890) | [ERT, INC](https://appshunter.io/developer/1160214546) |

## What reviewers say

### FLEX Study App

[App page](https://appshunter.io/ios/app/flex-study-app/id1627659963)

**In-app purchases:** none


### 15

[App page](https://appshunter.io/ios/app/15-06-ecoa/id6447290378)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is FLEX Study App free?

FLEX Study App is free to download, with no in-app purchases.

### Is 15 free?

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

### Do FLEX Study App or 15 have ads?

Neither FLEX Study App nor 15 shows ads.

### Which is updated more often, FLEX Study App or 15?

FLEX Study App ships an update every 5 months, and 15 every 3 months. Most recently, FLEX Study App was updated on May 16, 2026 and 15 on May 17, 2026.

---

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