Amazon EC2 Free tier - how many instances can I run

I am running a single instance t1.micro to host centos with an open source erp program Now I wish to also host another instance with a 2nd erp program. Will this be within my free tier limit.

Is there a count on the no# of instance I can use / start?

How many elastic Ip's can I associate?

For Question #1: Number of Instances

Amazon charges based on hours of usage, not based on number of instances you are running. Check this Amazon AWS Free tier details.

They have clearly mentioned that the free tier includes:

1. 750 hours of Amazon EC2 Linux/UNIX or RHEL or SLES Micro Instance usage (613 MB of memory and 32-bit and 64-bit platform support) – enough hours to run continuously each month*

2. 750 hours of Amazon EC2 Microsoft Windows Server‡ Micro Instance usage (613 MB of memory and 32-bit and 64-bit platform support) – enough hours to run continuously each month*

3. 750 hours of an Elastic Load Balancer plus 15 GB data processing*

4. 30 GB of Amazon Elastic Block Storage, plus 2 million I/Os and 1 GB of snapshot storage

For Question #2: Elastic IP addresses

Allocating and using one Elastic IP addresses per instance is basically free, except if the Elastic IP address is not currently associated with an instance, see section Elastic IP Addresses on page Amazon EC2 Pricing:

 $0.00 for one Elastic IP address associated with a running instance
 $0.005 per additional Elastic IP address associated with a running instance per hour on a pro rata basis
 $0.005 per Elastic IP address not associated with a running instance per hour on a pro rata basis
 $0.00 per Elastic IP address remap for the first 100 remaps per month
 $0.10 per Elastic IP address remap for additional remaps over 100 per month

It says,

> 750 hours of Amazon EC2 Linux/UNIX or RHEL or SLES Micro Instance usage (613 MB of memory and 32-bit and 64-bit platform support)

To clarify, if you have 2 EC2 instances run 24/7, that will make them a total of 1,488 hours in 31 days (1 month)

24 hrs * 31 days = 744 hours.
744 hours * 2 instances = 1,488 hours

If you don't want to pay an excess. Your 2 instances would only last around 15 days so it won't exceed 750 hours allocation per month.

Furthermore, this free tier expires in 12 month and only for new customers following your AWS sign-up date.

Amazon has a handy page that details everything under their free tier here: http://aws.amazon.com/free/

A single Micro instance running for 744 hours is free of charge, means you will be able to spin up two micros for half that alotted time, or three for a third. As soon as you go above 744 hours of micro compute you will be charged the standard $0.02/hr pricing.

As for the Elastic IPs, you will not be charged for one unless:

• The IP address is not attached to any running instance
• You have attached an IP address to an instance that already has an internet-routable IP address

If you're really cost adverse you can set up another Amazon account, the free tier last for 12 months and the Credit Card you need to provide is allowed to be the same for the accounts. As an extra note it's a nice way to have a cheaper dev environment (and also separates the environment nicely to boot!) You can then look into combining invoices and sharing resources between accounts as well.

As far as I know the free tier covers 750 machine hours of micro instances. You can probably run 750 machines for 1 hour and finish that quota in 1 hour. Or run 1 micro instance 24x7 and it will stay up for a whole month.

So you can only run one ec2 instance in the free tier.

Micro instances are not free if your free tier is up or you exceeded 750 micro instance hours per month.

Please refer the below FAQ from AWS -

Does an AWS customer have access to 750 instance hours each of the Linux and Windows t2.micro instances under the AWS Free Usage Tier?

Yes. A customer with access to the AWS Free Usage Tier can use up to 750 instance hours each of t2.micro instances running Linux and Windows. Usage of the Linux and Windows t2.micro instances are counted independently.