# Bunker One vs Saybolt Viscosity

The clearest difference is rating: Bunker One at 4.5 against Saybolt Viscosity's 3.0. Bunker One also leads on update cadence (every 3 months vs every 14 months). Saybolt Viscosity's advantage is iOS requirement (9.3 vs 15.6). On price, ratings volume, ads and in-app purchases there is nothing between them.

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

Bunker One holds the better App Store score, 4.5 against 3.0. Both are backed by a comparable volume of ratings — 2 and 2 respectively.

Bunker One ships an update every 3 months, Saybolt Viscosity every 14 months. Both last shipped on October 23, 2026.

## The numbers

| Metric | Bunker One | Saybolt Viscosity |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (2 ratings)](https://appshunter.io/ios/app/bunker-one/id439589227/reviews)** | [3.0 (2 ratings)](https://appshunter.io/ios/app/saybolt-viscosity/id631153914/reviews) |
| Number of ratings | 2 | 2 |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 14 months |
| Monetization | Free | Free |
| Size | 16 MB | 3 MB |
| Requires iOS | 15.6 | **9.3** |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Askapps](https://appshunter.io/developer/434706041) | [Saybolt International B.V.](https://appshunter.io/developer/493919167) |

## What reviewers say

### Bunker One

[App page](https://appshunter.io/ios/app/bunker-one/id439589227)

This app provides a suite of calculators for marine fuel standards, including CCAI, Cetan Index, and blending calculations. It supports ISO 8217 and ASTM standards, with all inputs and outputs in SI units. Users can also access news and updates from the developer.

**Highlights:** ISO 8217 fuel standard lookup, CCAI Number calculation, Cetan Index calculation (old & new methods), Fuel blending calculators (viscosity, sulphur), Injection temperature calculation, Energy and price relation calculations, News updates from developer

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

**In-app purchases:** none


### Saybolt Viscosity

[App page](https://appshunter.io/ios/app/saybolt-viscosity/id631153914)

This application serves as a calculator for converting viscosity and temperature values for petroleum fuels. It allows users to convert Kinematic Viscosity in Centistokes to desired target values across different temperature scales. In landscape mode, it transforms into a slider for visual comparison of viscosity units.

**Highlights:** Viscosity/Temperature conversion calculator, Converts Kinematic Viscosity (cSt), Supports Fahrenheit and Celsius, Landscape slider for unit comparison, Compares Centistokes to Saybolt Universal Seconds and Furol

**In-app purchases:** none


## Frequently asked questions

### Is Bunker One free?

Bunker One is free to download, with no in-app purchases.

### Is Saybolt Viscosity free?

Saybolt Viscosity is free to download, with no in-app purchases.

### Which has better reviews, Bunker One or Saybolt Viscosity?

Bunker One is rated higher. Bunker One averages 4.5 out of 5 from 2 ratings, while Saybolt Viscosity averages 3.0 from 2 ratings.

### Do Bunker One or Saybolt Viscosity have ads?

Neither Bunker One nor Saybolt Viscosity shows ads.

### Which is updated more often, Bunker One or Saybolt Viscosity?

Bunker One ships an update every 3 months, and Saybolt Viscosity every 14 months. Most recently, Bunker One was updated on October 23, 2026 and Saybolt Viscosity on October 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.*