What Is Reserved Instance?
A reserved instance is the capacity commitment that lowers your compute rate in exchange for a term. If you are asking what is reserved instance, picture a promise to run a defined instance configuration for one or three years, with the provider charging a lower rate than on demand in return. It is a unit cost lever, and it sits beneath any larger spend commitment you negotiate.
What is reserved instance in plain terms?
A reserved instance, almost always called an RI, is a commitment to a specific compute configuration for a one or three year term in return for a lower rate than on demand. As of June 2026, you commit to the instance type rather than a dollar figure, and you pay for the reservation whether or not the capacity runs. The deeper rate is the reward for taking that usage risk off the provider.
An RI is a unit cost tool, not a contract framework. It lowers the price of running a workload, but it does not negotiate the broader commercial terms of your relationship with the provider. That broader deal is a separate layer.
How it sits under a bigger commitment
A reserved instance stacks underneath a negotiated spend commitment. As of June 2026, an AWS enterprise discount program discount sits on top of reserved instances and savings plans rather than replacing them, so you keep lowering unit cost with RIs while the EDP discounts the committed spend above. The two operate on different layers of the same bill.
A reserved instance differs from a savings plan in what you commit to. An RI ties you to a defined configuration, while a savings plan commits an hourly dollar amount and flexes more broadly. RIs can reach deeper rates on stable workloads, savings plans trade some depth for flexibility.
The buyer risks to watch
The risk with a reserved instance is the same as any commitment: you pay for it whether or not you use it. As of June 2026, an RI bought against a workload that later shrinks or migrates becomes sunk cost. A three year term locks the rate but also locks you to a configuration that may not match where your architecture moves.
Size reservations to workloads you are confident will run for the full term, and keep volatile or uncertain demand on on demand pricing. The flexibility you keep is worth more than the marginal rate you would gain by over reserving.
Layering reservations under a bigger commitment? Book a confidential cloud commitment negotiation review before you sign.
What is a reserved instance in simple terms?
As of June 2026 a reserved instance, or RI, is a commitment to a specific compute configuration for a one or three year term in exchange for a lower rate than on demand. You commit to the instance type rather than a dollar figure, and you pay for the reservation whether or not you use it.
What is the difference between a reserved instance and a savings plan?
As of June 2026 a reserved instance commits you to a defined compute configuration, while a savings plan commits you to an hourly dollar amount and applies more flexibly across services. RIs can deliver deep rates on stable workloads, savings plans trade some of that depth for flexibility.
Does a reserved instance stack with an enterprise discount program?
Yes. As of June 2026 an AWS enterprise discount program discount stacks on top of reserved instances and savings plans. The RI lowers your unit rate and the EDP discounts the committed spend underneath, so the two work on different layers of the bill.
What happens to a reserved instance I do not use?
As of June 2026 you still pay for it. A reserved instance is a commitment, so unused capacity is sunk cost. Size reservations to workloads you are confident will run for the full term and keep volatile demand on on demand pricing.
Condense the commitment before you sign.
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