Rating Estimation
Norri’s rating estimation system provides content ratings (age classifications) for movies and TV shows, with intelligent fallbacks when official ratings aren’t available for your preferred country.
How It Works
1. Direct Match
If a rating exists for your preferred country (set in Library Settings), it’s displayed directly.
2. Fallback Countries
If your preferred country’s rating is unavailable, the system falls back to similar countries in order of cultural and geographic proximity:
| Preferred Country | Fallback Order |
|---|---|
| UK | US → IE → CA → AU → NZ |
| US | CA → GB → AU → NZ → IE |
| AU | NZ → GB → US → CA → IE |
| CA | US → GB → AU → NZ → IE |
| IE | GB → US → CA → AU → NZ |
| DE | FR → NL → GB → US |
| FR | DE → NL → GB → US |
| SE/NO/DK | Each other → DE → GB → US |
| JP | KR → US → GB |
| KR | JP → US → GB |
| IN | GB → US → AU |
When using a fallback rating, the source country code is shown in parentheses: 15 (US)
3. Estimated Ratings
If no fallback country has a rating, the system calculates an estimated rating based on all available ratings from other countries:
- Map each available rating to a normalized “age band” (0, 10, 13, 16, 18)
- Calculate the median age band (robust against outliers)
- If the number of ratings is even, round up (conservative approach)
- Map the median age band back to your preferred country’s rating system
Estimated ratings are shown with an asterisk: 12A*
Visual Indicators
| Display | Meaning |
|---|---|
15 | Direct match for your preferred country |
R (US) | Fallback rating from another country |
12A* | Estimated rating (asterisk indicates estimation) |
Supported Rating Systems
English-Speaking Countries
| Country | Ratings |
|---|---|
| UK (GB) | U, PG, 12A, 12, 15, 18 |
| US | G, PG, PG-13, R, NC-17 |
| AU | G, PG, M, MA15+, R18+ |
| CA | G, PG, 14A, 18A, R |
| IE | G, PG, 12A, 15A, 18 |
| NZ | G, PG, M, R16, R18 |
Europe
| Country | System | Ratings |
|---|---|---|
| DE (Germany) | FSK | 0, 6, 12, 16, 18 |
| FR (France) | — | U, 10, 12, 16, 18 |
| NL (Netherlands) | Kijkwijzer | AL, 9, 12, 16, 18 |
| SE (Sweden) | — | Btl, 7, 11, 15 |
| NO (Norway) | — | A, 6, 12, 15, 18 |
| DK (Denmark) | — | A, 7, 11, 15 |
Asia
| Country | System | Ratings |
|---|---|---|
| JP (Japan) | Eirin | G, PG12, R15+, R18+ |
| KR (South Korea) | KMRB | All, 12, 15, 18 |
| IN (India) | CBFC | U, U/A, A |
Rating Equivalency
Ratings are mapped to normalized age bands for cross-country estimation:
| Age Band | US | UK | AU | DE | FR | CA | JP | IN |
|---|---|---|---|---|---|---|---|---|
| All Ages | G | U | G | 0 | U | G | G | U |
| ~10 | PG | PG | PG | 6 | 10 | PG | G | U |
| 12-13 | PG-13 | 12A | M | 12 | 12 | 14A | PG12 | U/A |
| 15-16 | R | 15 | MA15+ | 16 | 16 | 18A | R15+ | U/A |
| 18+ | NC-17 | 18 | R18+ | 18 | 18 | R | R18+ | A |
Library Settings
Each library can configure:
- Rating Country — Your preferred country for displaying ratings
- Show Estimated Ratings — Toggle whether to show estimated ratings when direct/fallback ratings aren’t available (enabled by default)
When estimated ratings are disabled, no rating badge is shown if data isn’t available for your preferred or fallback countries.
Data Sources
Rating data comes from TMDB via their release_dates endpoint. TMDB includes theatrical, digital, and physical (DVD/Blu-ray) release ratings. Norri prefers theatrical ratings, falling back to digital or physical when unavailable.
Limitations
- TMDB’s certification data is crowd-sourced and may be incomplete for some countries
- Some films may not have any certification data available
- The estimation algorithm provides a best-guess but may not match official ratings
- Historical films may have different ratings than when originally released