As you know, each platform has its own system of reviewing. They have different scales, they have different categories... This article explains how they all fit into the Smily core system.

The review rating scale that Smily has adopted in the review section is from 1 to 5.

- For the platforms like Airbnb that use the same scale, you will find the exact same rating in Smily.
- For the platforms that use a different scale, like Booking.com, we convert
the notation to a 1 to 5 scale. We apply a mathematical formula so that
the value of the 1..10 scale has the same weight as a 1..5 scale.

If you love maths, here is the formula

1..5 rating = 1 + (rating - 1) x 4 / (max rating - min rating)

*example with the 1..10 rating as in Booking.com, if you get a 9, it will be worth*

*1 + (9 - 1) x 4 / (10 - 1) = 4,56, rounded to 4.6*

Conversion from a 1 to 10 scale

Channel rating |
Smily rating (rounded) |
Stars |

1 | 1 | 1 |

2 | 1.4 | 1.5 |

2.5 | 1.7 | 1.5 |

3 | 1.9 | 2 |

4 | 2.3 | 2.5 |

5 | 2.8 | 3 |

6 |
3.2 | 3 |

7 | 3.7 | 3.5 |

7.5 | 3.9 | 4 |

8 | 4.1 | 4 |

9 | 4.6 | 4.5 |

10 |
5 |
5 |

If a rating category is not present on one of the platforms, it is simply left blank on Smily.