That depends. Is the battery almost fully discharged? Are you checking to see if it's charging after an hour or so?
The first 4 or 5 hours on "charge" for a fully discharged battery is the ramp-up period - it gets almost no actual charge. Let it sit on the charger - turned off, it's a charger, not a power supply to run the phone - for 24 hours. Then see if the battery is charged.
In the future, if you want the longest battery life, charge the battery when it's down to about 50%. Running it all the way down cuts the life by 50% or more.