# NFP Calendar vs Sisu Longevity Studio

The clearest difference is update cadence: Sisu Longevity Studio at fortnightly against NFP Calendar's every 2 months. Sisu Longevity Studio also leads on iOS requirement (16.0 vs 26.0). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

NFP Calendar ships an update every 2 months, Sisu Longevity Studio fortnightly. The most recent releases landed on October 22, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | NFP Calendar | Sisu Longevity Studio |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (3 ratings)](https://appshunter.io/ios/app/nfp-calendar/id6751753267/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Fortnightly** |
| Monetization | Free | — |
| Size | 8 MB | 194 MB |
| Requires iOS | 26.0 | **16.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 12+ | 4+ |
| Developer | [Esteban Cervera](https://appshunter.io/developer/1209785445) | [Sisu Longevity Studio LLC](https://appshunter.io/developer/1896493102) |

## What reviewers say

### NFP Calendar

[App page](https://appshunter.io/ios/app/nfp-calendar/id6751753267)

Track your fertility naturally using various methods like Creighton or Billings. Record daily observations, manage your cycle, and export data for your instructor or doctor. Designed specifically for Natural Family Planning users.

**Highlights:** Record mucus observations, Track menstrual flow, Log intercourse timing, Automatic cycle detection, Generate PDF charts, Export data as JSON, iCloud sync

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

**In-app purchases:** none


### Sisu Longevity Studio

[App page](https://appshunter.io/ios/app/sisu-longevity-studio/id6767615111)

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

**In-app purchases:** none


## Frequently asked questions

### Is NFP Calendar free?

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

### Is Sisu Longevity Studio free?

Sisu Longevity Studio is free to download, with no in-app purchases.

### Do NFP Calendar or Sisu Longevity Studio have ads?

Neither NFP Calendar nor Sisu Longevity Studio shows ads.

### Which is updated more often, NFP Calendar or Sisu Longevity Studio?

NFP Calendar ships an update every 2 months, and Sisu Longevity Studio fortnightly. Most recently, NFP Calendar was updated on October 22, 2026 and Sisu Longevity Studio 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.*