I have a new charge on my AWS account yesterday (~$40). When I dug in a bit it comes from a category called USW2-HeavyUsage:r4.large($). I know what the USW2 is for and what the r4.large is for. What is the HeavyUsage referring to?

the r4.large is an AWS' reserved instance where I have reserved r4.large for 3 years. Does this reservation come with a limit on usage?

  • 1
    Have you paid all upfront, partial upfront, or no upfront? If you haven't paid all upfront it's probably your discounted hourly fee.
    – Tim
    Apr 2, 2019 at 23:50
  • @Tim I've paid none upfront. Does AWS charge this monthly in advance?
    – Joe B
    Apr 3, 2019 at 4:28
  • 1
    If you've reserved the instance and paid nothing then this is most likely the hourly fee associated with that instance.
    – Tim
    Apr 3, 2019 at 8:20
  • @Tim I calculated the hourly usage for the upcoming month and that is indeed the amount I was charged. Do you know why AWS charges you before the instance's usage instead of at the end of the month (after usage)?
    – Joe B
    Apr 3, 2019 at 16:19
  • At the end of the month @JoeB
    – Aslan
    Feb 1, 2023 at 10:58

2 Answers 2


You have committed to pay for this type of server for three years with a no upfront payment. This line item is the monthly fee for the server you have reserved.

AWS payment is typically in arrears as it's usage base. Given this is taken in advance I guess it's because they know in advance what the fee will be.

  • 5
    How strange, why dont they just say "Reserving Cost" or something.
    – Paul
    Nov 14, 2019 at 9:23
  • AWS naming can be a bit random / misleading at times. See also the new "savings plan", which is somewhat similar to reserved instances.
    – Tim
    Nov 14, 2019 at 18:31
  • 1
    Slight correction needed: "with a no upfront reservation" -> "with no upfront payment"
    – Aslan
    Feb 1, 2023 at 10:55

I was under the impression that AWS discontinued the Light / Medium / Heavy Utilization Reserved instances. For their description look here: EC2 Reserved Instance Options, however note that the Light and Medium options are no longer available.

Essentially the heavy utilization means that your instance is running 24/7. It doesn't matter how busy the instance was, only that it was on.

These options were quite confusing and I believe they're no longer offered.

Hope that helps :)

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