# SigmaNote vs Causal Loop Diagram

The clearest difference is in-app purchases: Causal Loop Diagram at none against SigmaNote's 4. Causal Loop Diagram also leads on iOS requirement (16.0 vs 18.0). SigmaNote's advantage is update cadence (weekly vs every 3 weeks). On price, ads and device support there is nothing between them.

Both are free to download. SigmaNote sells 4 in-app purchases, starting at $8.99 per month. Causal Loop Diagram asks for nothing beyond the download.

SigmaNote ships an update weekly, Causal Loop Diagram every 3 weeks. The most recent releases landed on June 1, 2026 and September 23, 2026 respectively.

## The numbers

| Metric | SigmaNote | Causal Loop Diagram |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/sigmanote/id6744374542/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Weekly** | Every 3 weeks |
| Monetization | Freemium | — |
| Size | 90 MB | 4 MB |
| Requires iOS | 18.0 | **16.0** |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [SignifyID LLC](https://appshunter.io/developer/1793292360) | [seiji honda](https://appshunter.io/developer/1896430544) |

## What reviewers say

### SigmaNote

[App page](https://appshunter.io/ios/app/sigmanote/id6744374542)

This app acts as an AI-powered knowledge hub, allowing users to capture, manage, learn from, and create knowledge across various formats. It uses AI agents to organize content, answer questions, and facilitate voice-driven writing and content creation.

**Highlights:** Capture knowledge from diverse sources, AI agents for organization and retrieval, Learn through conversation and listening, Voice-driven AI writing and content creation, Unified knowledge lifecycle management, Cross-format knowledge integration

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| SigmaNote Premium Monthly | $8.99 | per month |
| SigmaNote Premium Plus Monthly | $12.99 | per month |
| SigmaNote Premium Yearly | $80.99 | per year |
| SigmaNote Premium Plus Yearly | $116.99 | per year |


### Causal Loop Diagram

[App page](https://appshunter.io/ios/app/causal-loop-diagram/id6769942289)

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

**In-app purchases:** none


## Frequently asked questions

### Is SigmaNote free?

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

### Is Causal Loop Diagram free?

Causal Loop Diagram is free to download, with no in-app purchases.

### Do SigmaNote or Causal Loop Diagram have ads?

Neither SigmaNote nor Causal Loop Diagram shows ads.

### Which is updated more often, SigmaNote or Causal Loop Diagram?

SigmaNote ships an update weekly, and Causal Loop Diagram every 3 weeks. Most recently, SigmaNote was updated on June 1, 2026 and Causal Loop Diagram on September 23, 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.*