# Sigma Notepad Calculator vs Therapy Notebook TD

Sigma Notepad Calculator and Therapy Notebook TD 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. Sigma Notepad Calculator sells 3 in-app purchases, starting at $1.99 per month and Therapy Notebook TD sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

Both ship on a similar rhythm, roughly fortnightly. The most recent releases landed on October 25, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Sigma Notepad Calculator | Therapy Notebook TD |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Fortnightly | Fortnightly |
| Size | 16 MB | 30 MB |
| Requires iOS | **17.0** | 18.0 |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [Soules Studio Ltd](https://appshunter.io/developer/1883253392) | [Alper CUHADAROGLU](https://appshunter.io/developer/6776618833) |

## What reviewers say

### Sigma Notepad Calculator

[App page](https://appshunter.io/ios/app/sigma-notepad-calculator/id6768903761)

**Features:** Family Sharing

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $1.99 | per month |
| Annual | $14.99 | per year |
| Lifetime | $29.99 | one-time |


### Therapy Notebook TD

[App page](https://appshunter.io/ios/app/therapy-notebook-td/id6776618831)

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Therapy Notebook Premium | $2.99 | per month |
| Therapy Notebook Premium | $29.99 | per year |


## Frequently asked questions

### Is Sigma Notepad Calculator free?

Sigma Notepad Calculator is free to download, with in-app purchases available.

### Is Therapy Notebook TD free?

Therapy Notebook TD is free to download, with in-app purchases available.

### Do Sigma Notepad Calculator or Therapy Notebook TD have ads?

Neither Sigma Notepad Calculator nor Therapy Notebook TD shows ads.

### Which is updated more often, Sigma Notepad Calculator or Therapy Notebook TD?

Sigma Notepad Calculator ships an update fortnightly, and Therapy Notebook TD fortnightly. Most recently, Sigma Notepad Calculator was updated on October 25, 2026 and Therapy Notebook TD on October 24, 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.*