How long does it take to treat a fungal nail infection?

Fungal nails. Usually it takes nails on the feet if non diabetic 6 to 8 months to grow out when using treatment of either laser, oral and topical. I suggest to use biotin to help speed up the growth of the nail when getting treatments.
It depends ... It depends on the individual, the severity of the infection, and the type of treatment. Have your nails evaluated and get the appropriate treatment.
Sometime months . Nails grow very slowly and thus you need the medicine for months. It also depends on the rest of your health status, your ability to tolerate the medication without side effects.
PILLS VS. TOPICALS. The pill terbinafine is taken daily for 3 months; I quote a 70% success rate, and maybe up to a year to look "normal." Anti-fungal solutions are applied daily, maybe using them up to a year. I have very little success with topicals. Dr. Latva.
Patience advised. Regardless of whatever treatment option you use (topical, oral, laser, etc.), it generally takes months to over a year to treat a fungal nail infection. Generally, the healthier and younger you are the quicker your nails will heal, if at all. You must be patient with whatever treatment you use because treating fungal nails can be a long task.