Android Studio gradle takes too long to build

Question

My Android Studio project used to build faster but now it takes a long time to build. Any ideas what could be causing the delays? I have tried https://stackoverflow.com/a/27171878/391401 but no effect. I haven't any Anti virus running which could interrupt the builds. My app is not that big in size as well (around 5MB) and it used to build within few seconds but not sure what has changed.

10:03:51 Gradle build finished in 4 min 0 sec  
10:04:03 Session 'app': running  
10:10:11 Gradle build finished in 3 min 29 sec  
10:10:12 Session 'app': running  
10:20:24 Gradle build finished in 3 min 42 sec  
10:28:18 Gradle build finished in 3 min 40 sec  
10:28:19 Session 'app': running  
10:31:14 Gradle build finished in 2 min 56 sec   
10:31:14 Session 'app': running  
10:38:37 Gradle build finished in 3 min 30 sec  
10:42:17 Gradle build finished in 3 min 40 sec  
10:45:18 Gradle build finished in 3 min 1 sec  
10:48:49 Gradle build finished in 3 min 30 sec  
10:53:05 Gradle build finished in 3 min 22 sec  
10:57:10 Gradle build finished in 3 min 19 sec  
10:57:11 Session 'app': running  

Answer 1

In Android Studio go to File -> Settings -> Build, Execution, Deployment -> Build Tools -> Gradle

(if on mac) Android Studio -> preferences... -> Build, Execution, Deployment -> Build Tools -> Gradle

Check the 'Offline work' under 'Global Gradle settings'

Note: In newer version of Android studio, View->Tool Windows->Gradle->Toggle button of online/offline

It will reduce 90% gradle build time.

if you just added a new dependency in your gradle you will have to uncheck the offline work or gradle will not be able to resolve the dependencies. After the complete resolving then you you can check the offline work for a faster build