It depends where you start. I started in Saint Jean Pied de Port in France and made it to Santiago de Compostela in 35 days. It was over 800 km of walking with distances per day varying between 19 km and 34 km. I had 3 rest days during the 5 weeks.
People start their journey at various places with the most popular starting point in Sarria just over 100km from Santiago. about 6 years ago