The Hanbali school, prevalent in Saudi Arabia and Qatar and influential well beyond, treats shortening as the better choice for a traveller while accepting a full prayer as valid. Its rules on distance are close to the Shafi'i and Maliki ones, but its stay limit is counted in prayers.
The travel distance
The standard position in works such as Ibn Qudamah's al-Mughni is 16 farsakh, or four burud, following the reports from Ibn Abbas and Ibn Umar. This is usually converted to about 80 km, with some scholars giving 81 or 89 km.
When qasr begins
Once you pass the inhabited houses of your town, you may shorten. You remain a traveller until you return to them.
Shortening is better
For the Hanbalis, qasr is better than completing the prayer, and Imam Ahmad is reported to have disliked completing without reason. Completing remains valid.
The stay limit: more than 20 prayers
If you intend to stay long enough to pray more than 20 obligatory prayers at your destination, roughly more than four days, you pray in full from arrival. This is based on the Prophet's ﷺ arrival in Makkah on the fourth of Dhul-Hijjah before the Farewell Hajj, when he shortened until he left for Mina on the eighth. If you stay without a fixed intention, waiting for a need to be met, you keep shortening however long it lasts.
Combining prayers
A traveller may combine Dhuhr with Asr and Maghrib with Isha, early or late. The Hanbalis also allow combining for other genuine needs, such as illness or heavy rain. Many scholars say it is better not to combine when settled at your destination unless there is a need.
Sunnah prayers
The regular sunnah prayers attached to Dhuhr, Maghrib and Isha are normally left while travelling, following the practice of Ibn Umar. The sunnah of Fajr and the witr are kept, as the Prophet ﷺ never left them.
Ibn Taymiyyah's view
Shaykh al-Islam Ibn Taymiyyah, a Hanbali scholar, argued that the Qur'an and Sunnah set no fixed distance or stay. A journey is whatever people customarily call a journey ('urf), and a traveller keeps shortening until they settle. Shaykh Ibn Uthaymin followed a similar view. Other contemporary scholars, including Shaykh Ibn Baz, kept to the approximate 80 km and four-day limits for clarity.
Check your trip with the Hanbali setting in the calculator.