Family name Fastus (Faste 
, Fash 
, Fasto 
) , throughout the world, is quite a rare last name. The family name Fastus is characteristic of Cameroon, where it is a rare surname, United Arab Emirates, and Syria. Measured by absolute frequency, it is the most numerous in Nigeria, the United States, and Indonesia. Likewise, Fastus is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Faste | Democratic Republic of the Congo, United States, India, Myanmar, Germany |
| Fash | United States, Nigeria, Cameroon, Indonesia, Germany |
| Fasto | United Kingdom, Italy, United States, Nigeria, Indonesia |
| Fastus | United States, Nigeria, Romania, Germany |