The main story in Fallout 4 can vary depending on your playstyle and how much you explore. Generally, it could take around 20-30 hours to complete the main quests.
The length of the main story in Fallout 4 is not fixed. If you rush through the main quests without doing much side content, it might take you about 15-20 hours. But if you take your time and explore all the available options, it could easily stretch to 30-40 hours or more.
The main story of Fallout 4 typically lasts between 25 and 35 hours. This estimate assumes a moderate pace of play and some exploration of the game world. However, your actual playtime could be shorter or longer depending on your gaming habits and how deeply you engage with the game's various elements.