I just upgraded my daughters plan . I thought my billing cycle was the 22nd of the month so I did it today online . I just found out my cycle starts on the 21st So does this mean I will be charged extra.and if so how much
No, there's a process called proration that's going to be applied.
You divide the amount of data/minutes you have by the amount of days in your billing cycle (30 days), then you multiply that by the number of days until your next bill.
EX: 1GB data = 1024 MB.
plan change date, April 22nd. Next Bill date, April 30th
1024MB / 30 days = 34.13
34.13 * 8 days = 273 MB data available to use until your next bill.
Same for the minutes and the price of the plan.
Fees for monthly service are paid in advance
On your first bill you will be charged for the following:
One full month of service, for the upcoming month
A partial month of service, for the period of time between "now" and the start of that (above) "full" month
Any taxes or other additional fees related to the above charges
Plan 1 : 40$
Plan 2 : 60$
Let's say you stay 10 days on the first plan before changing.
10/30 * 40 = 13.3$
20 days on the new plan :
20/30 * 60 = 40$
Total of 53.3$. It may be a bit higher in THIS case. But in your case the difference will not even be big enough to be remarked.