As a student, your free time — the time that you're not in sitting class, doing activities, eating, or partying — is your available study time. 

But some free time is too small to use for studying and every student is different.

That's why in Shovel you can set what is YOUR Minimum Study Time block so that Shovel doesn't count the small slivers of time in your schedule as Study Time.

To adjust your Minimum Study Time Block 

Step 1: User menu in bottom left > Adjust study time 

Step 2: Adjust the Minimum Study Time Block slider

Any free time block that is longer than the value you set will be Study Time and any free time block that is shorter than the value you set will be Extra time.