Making up missed prayers
What you should do is calculate the number of missed prayers you have.
For example:
Suppose you missed 4 years of prayer.
There are 365 days in a year. Before you multiply 365 days by five prayers, subtract the number of days you may have missed because you were menstruating. For example, suppose you were menstruating 84 days of the year. Subtract 84 from 365. You get 281 days of missed prayers. Multiply this by 4 and you get 1124 days of missed prayers total.
This is about 5620 prayers. If you prayer an extra five prayers a day, you can make up these prayers in about three years.
To keep it simple, just double up your prayers for the next three years.
So when you pray your fajr prayer, for example, make an extra fajr prayer. When you pray dhuhr, make an extra dhuhr prayer as a makeup. Insha’Allah, if you can do this consistently for three years, you’ll have made up all your prayers.
I hope this helps.
By Asif Iqbal