# SAI Chart vs Previa

The clearest difference is in-app purchases: SAI Chart at none against Previa's 3. SAI Chart also leads on update cadence (every 10 days vs every 2 months) and iOS requirement (15.6 vs 17.6). On price, ads and device support there is nothing between them.

Both are free to download. Previa sells 3 one-off in-app purchases. SAI Chart asks for nothing beyond the download.

SAI Chart ships an update every 10 days, Previa every 2 months. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | SAI Chart | Previa |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (6 ratings)](https://appshunter.io/ios/app/previa/id6767003039/reviews)** |
| Number of ratings | — | **6** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 10 days** | Every 2 months |
| Monetization | — | Free |
| Size | 68 MB | 9 MB |
| Requires iOS | **15.6** | 17.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 17+ | 17+ |
| Developer | [SCRIBERUNNER LLC](https://appshunter.io/developer/1876520576) | [Dmitriy Kourtchikov](https://appshunter.io/developer/1891158262) |

## What reviewers say

### SAI Chart

[App page](https://appshunter.io/ios/app/sai-chart/id6759046519)

**In-app purchases:** none


### Previa

[App page](https://appshunter.io/ios/app/previa/id6767003039)

Prepare for doctor's appointments by describing your symptoms. This AI-powered tool identifies potential overlooked symptoms and suggests relevant tests to discuss with your physician. It prioritizes your health information for more productive consultations, keeping all data private on your device.

**Highlights:** AI symptom analysis, Prioritized test recommendations, Session history, Report translation, Recipient tracking, Profile-aware analysis, Multi-language support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Previa Basic Pack | $0.99 | one-time |
| Previa Standard Pack | $1.99 | one-time |
| Previa Value Pack | $3.49 | one-time |


## Frequently asked questions

### Is SAI Chart free?

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

### Is Previa free?

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

### Do SAI Chart or Previa have ads?

Neither SAI Chart nor Previa shows ads.

### Which is updated more often, SAI Chart or Previa?

SAI Chart ships an update every 10 days, and Previa every 2 months. Most recently, SAI Chart was updated on October 24, 2026 and Previa on October 25, 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.*