So its after business hours and you are not quite sure whether you want to “Stop” or “Terminate” your EC2
instance. Whats the difference ?

“Stop”ping an EC2 instance:

“Stop”ping  an ec2 instance differs from “Terminate”ing an EC2 instance since you cannot restart a terminated instance. Because Amazon S3-backed AMIs can’t be stopped, they’re either running or terminated. You can stop an Amazon EBS backed instance, but not an s3-backed instance.

When the instance is stopped, you’re not charged for any instance hours, only the storage volume.Each time you transition an instance from stopped to started, Amazon charges a full instance hour, even if transitions happen multiple times within a single hour.

If you were using an “elastic IP address” with the instance, the address is automatically concealed when the instance stops. While the instance is stopped, you’re charged for the address being unmapped ( unless you remap it to another instance ).

“Terminate”ing an EC2 instance:

On the other hand,when an instance is terminated, any storage is deleted.
By default, any volumes that were created when the instance launched( the root device and any others specified in the block device mapping) are automatically deleted when the instance terminates.

However, any volumes that you attached after the instance was running are not deleted. If you detach and then re-attach a volume that was created at instance launch, it’s treated like a new volume that you attached after the launch, it will persist after instance termination and you will continue being charged for it unless you terminate it.