I'm not understanding how the partial upfront work for ec2 reserved instances. I'm trying to calculate how much the instance will cost on one year.

If, for example, I add an m4.xlarge instance reserved for one year with partial upfront on AWS Calculator it returns the following information on the estimate tab:

Amazon EC2 Service (US-East): 702.02
- Compute: 54.02
- Reserved Instances (One Time Fee): 648.00

Total One-Time Payment: 648.00
Total Monthly Payment: 54.02

My doubt is if the monthly payment is included in the first month.

Should I calculate the cost of an entire year as 648 + 12 * 54.02? Or the cost is 648 + 11 * 54.02?



Full year (x12). Amazon's cost-model doesn't pre-pay hourly costs like that. It's either up-front one-time, or hourly. No middle ground.

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    Please look at aws.amazon.com/ec2/faqs/#reserved-instances You can purchase a reserved instance and pay a partial upfront fee to have a smaller hourly rate – Dimas Kotvan Oct 5 '15 at 18:56
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    @DimasKotvan Smaller hourly rate is still an hourly rate, and it will be charged at that hourly rate for the full 12 months of the term. You don't get one month free. – sysadmin1138 Oct 5 '15 at 19:01

I found the answer on Amazon EC2 FAQ

**Q: How do I calculate the list value of an RI?**

Here is a sample list value calculation for 3yr Partial Upfront RIs:

3yr Partial Upfront Volume Discount Value in US-East

             Upfront $    Recurring Hourly $    Recurring Hourly Value    List Value

m3.xlarge    $ 1,345      $ 0.060               $ 1,577                   $ 2,922
c3.xlarge    $ 1,016      $ 0.045               $ 1,183                   $ 2,199

Assume 26,280 Hours in a 3yr Term
Recurring Hourly Value = Recurring Hourly $ * Hours in Term
List Value = Upfront $ + Recurring Hourly Value

So the answer is that I need to sum the first payment with 12 * the month value

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