Tell if battery goes from 40 to 20 percent in 8hrs in iphone, is this normal?

Actualy it drains 1percent/30mins on standby
its on ios 6.1,
location services, backgrounds apps, push notifications are off
at night at 11.00 pm it was at 40 percent, now its mornin 7.15 am and its 19 percent, is this normal?

How's your pregnant phone doing?

How old is the Phone because it would have a Lithium Ion battery, and they aren't as good as they make out they are.

It's ok

Do you have the screen contrast on high or low?

High would drain it fast.

Omg your phone is pregnant? Congrats

If you have used your phone between 11-7:15 it is normal… But if you've not… It's not normal…
You can try the following tricks
1) switch your internet off when you're not using it
2) reduce the brightness
3) edit your spotlight list (settings>general>spotlight search)… And uncheck the apps you don't use
4) keep your phone switched off at night when you're sleeping
5) try to complete 2 charge cycles in a month (charge it fully I.e 100% and then don't charge it till it's 0% again… That completes 1 cycle)
I was facing somewhat the same problem… And these things helped me a lot

It''s ok