# Interpolation Methods vs Should I Sail

The clearest difference is price: Should I Sail at Free against Interpolation Methods's $1.99. Should I Sail also leads on update cadence (every 10 days vs every 2 months) and iOS requirement (15.1 vs 17.0). Interpolation Methods's advantage is in-app purchases (none vs 1). On ads and device support there is nothing between them.

Should I Sail is free to download; Interpolation Methods costs $1.99 up front. Should I Sail sells 1 in-app purchase, starting at $49.99 per year. Interpolation Methods asks for nothing beyond the download.

Interpolation Methods ships an update every 2 months, Should I Sail every 10 days. The most recent releases landed on November 11, 2026 and November 13, 2026 respectively.

## The numbers

| Metric | Interpolation Methods | Should I Sail |
| --- | --- | --- |
| Price | $1.99 | **Free** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 10 days** |
| Size | 10 MB | 71 MB |
| Requires iOS | 17.0 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Irving Josue Cortes Iturriaga](https://appshunter.io/developer/1750836580) | [Eran Yanikov](https://appshunter.io/developer/1894491830) |

## What reviewers say

### Interpolation Methods

[App page](https://appshunter.io/ios/app/interpolation-methods/id6557032923)

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

**In-app purchases:** none


### Should I Sail

[App page](https://appshunter.io/ios/app/should-i-sail/id6762515261)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Should I Sail Pro | $49.99 | per year |


## Frequently asked questions

### Is Interpolation Methods free?

Interpolation Methods costs $1.99, with no in-app purchases.

### Is Should I Sail free?

Should I Sail is free to download, with in-app purchases available.

### Do Interpolation Methods or Should I Sail have ads?

Neither Interpolation Methods nor Should I Sail shows ads.

### Which is updated more often, Interpolation Methods or Should I Sail?

Interpolation Methods ships an update every 2 months, and Should I Sail every 10 days. Most recently, Interpolation Methods was updated on November 11, 2026 and Should I Sail on November 13, 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.*