# SubSum vs BaiPDF

The clearest difference is in-app purchases: SubSum at none against BaiPDF's 9. SubSum also leads on iOS requirement (17 vs 26.0). BaiPDF's advantage is update cadence (daily vs every 4 months). On price, ads and device support there is nothing between them.

Both are free to download. BaiPDF sells 9 in-app purchases, starting at $3.49 per month. SubSum asks for nothing beyond the download.

SubSum ships an update every 4 months, BaiPDF daily. The most recent releases landed on September 9, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | SubSum | BaiPDF |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Daily** |
| Size | 2 MB | 9 MB |
| Requires iOS | **17** | 26.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [桥 汪](https://appshunter.io/developer/1658027527) | [Uzero Technology](https://appshunter.io/developer/1485380269) |

## What reviewers say

### SubSum

[App page](https://appshunter.io/ios/app/subsum/id6754885566)

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

**In-app purchases:** none


### BaiPDF

[App page](https://appshunter.io/ios/app/baipdf-scan-and-pdf-convert/id6781993555)

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

**In-app purchases (9)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Membership | $3.49 | per month |
| Quarterly Membership | $6.99 | per 3 months |
| Yearly Membership | $11.99 | per year |
| 30-Page Pack | $1.29 | one-time |
| 100-Page Pack | $1.79 | one-time |
| 200-Page Pack | $2.49 | one-time |
| 500-Page Pack | $4.99 | one-time |
| 1,000-Page Pack | $7.49 | one-time |
| 5,000-Page Pack | $34.99 | one-time |


## Frequently asked questions

### Is SubSum free?

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

### Is BaiPDF free?

BaiPDF is free to download, with in-app purchases available.

### Do SubSum or BaiPDF have ads?

Neither SubSum nor BaiPDF shows ads.

### Which is updated more often, SubSum or BaiPDF?

SubSum ships an update every 4 months, and BaiPDF daily. Most recently, SubSum was updated on September 9, 2026 and BaiPDF on September 10, 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.*