# TBD vs Survey C

The clearest difference is in-app purchases: TBD at none against Survey C's 1. TBD also leads on iOS requirement (13.0 vs 17.6). Survey C's advantage is update cadence (weekly vs every 5 weeks). On price, ads and device support there is nothing between them.

Both are free to download. Survey C sells 1 one-off in-app purchase. TBD asks for nothing beyond the download.

TBD ships an update every 5 weeks, Survey C weekly. The most recent releases landed on October 8, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | TBD | Survey C |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 5 weeks | **Weekly** |
| Size | 19 MB | 5 MB |
| Requires iOS | **13.0** | 17.6 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 12+ |
| Developer | [Hangzhou Dashi Wisdom Technology Co., Ltd.](https://appshunter.io/developer/1822219570) | [Ngoc Tung Nguyen](https://appshunter.io/developer/1123458177) |

## What reviewers say

### TBD

[App page](https://appshunter.io/ios/app/tbd-flowmeter/id1632862012)

**Features:** macOS Compatibility

**In-app purchases:** none


### Survey C

[App page](https://appshunter.io/ios/app/survey-c-plus-autocad-export/id6756013455)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $200.00 | one-time |


## Frequently asked questions

### Is TBD free?

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

### Is Survey C free?

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

### Do TBD or Survey C have ads?

Neither TBD nor Survey C shows ads.

### Which is updated more often, TBD or Survey C?

TBD ships an update every 5 weeks, and Survey C weekly. Most recently, TBD was updated on October 8, 2026 and Survey C on October 7, 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.*