Is iphone 5S battery life better than iphone 5 battery life?

I just want to know, cause IIm gonna to buy a 5s

That really depends on the setting. Brightness, Wi-Fi, app running in the background, etc. If your looking for a longer battery than I recommend you spend an extra $80-100 for a mophie case because that lets you have a second battery in your case and switch the battery on and it will charge your iphone.

5S does have a better battery then 5, but the overall hardware is all greatly improved over 5.

Yes, however, I recommend getting an Android phone if you worry about battery life because iPhones don't have very good battery life compared to Android phones but to answer your question, YES.

The iPhone 5s has a 1560mAh battery. This is an 8% increase from the 1440mAh battery in the iPhone 5.

Critical reviews have notice that the iPhone 5s battery indeed outlasts the iPhone 5 battery.

Trusted Reviews.com says,

"We got between 9 and 10 hours of mixed usage, including streaming video, gaming, browsing, calls, taking pictures and video and listening to music.

Impressively, streaming 720p video at half screen brightness seemed to tax the battery very little, with only 3% disappearing in HALF AN HOUR. Playing music stored locally using the included Earpods at high volume saw of a 4% drop in 30 mins. Gaming, particularly intense 3D games such as Real Racing 3 and Infinity Blade 3, sapped juice at a steady, but reasonable, rate while 3G browsing was the other main drain.

Used normally we managed to make the battery last for a DAY AND A HALF before requiring a charge, better than the iPhone 5."

In conclusion, the iPhone 5s's battery life is significantly longer than the iPhone 5's. Trusted Reviews (above) says the battery lasted A DAY AND A HALF before requiring an additional charge. I'm glad to hear that you're going to get an iPhone 5s! Congratulations on your purchase!

While the 5S has slightly more battery capacity, the battery life depends way more on how you use the phone than on which model you buy.

Well seeing as the 5s has a bigger battery powering the same size display, yea.