Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Total savings over term
$599.18
Savings percentage
39.6%
On-demand total cost
$1,513.73
Reserved total cost
$914.54
Break-even utilization needed
0.0%
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How to use this
- 1Enter on-demand hourly rate ($).
- 2Enter reserved hourly rate ($).
- 3Enter upfront payment ($).
- 4Enter commitment term (years).
- 5Enter expected utilization (%).
- 6Read your total savings over term on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Reserved instances, savings plans, and committed-use discounts trade a usage commitment for a lower hourly rate, but they only pay off if your usage stays above the committed level for the full term. This calculator compares total on-demand cost against total reserved cost (including any upfront payment) over the commitment term, and reports the break-even utilization — the minimum percentage of time the instance needs to run for the reservation to beat paying on-demand. It also flags the total dollar savings at your entered utilization rate. The number that trips people up is the break-even utilization: a 1-year no-upfront reservation typically breaks even around 55-65% utilization, meaning you come out ahead even if the instance sits idle over a third of the time, which is why reservations make sense for baseline production load even with some slack for variability.
Worked example
Using the values the calculator loads with:
Inputs
- On-demand hourly rate: 0.192 $
- Reserved hourly rate: 0.116 $
- Upfront payment: 0 $
- Commitment term: 1 years
- Expected utilization: 90 %
Results
- Total savings over term: $599.18
- Savings percentage: 39.6%
- On-demand total cost: $1,513.73
- Reserved total cost: $914.54
- Break-even utilization needed: 0.0%
What each field means
Inputs
- On-demand hourly rate ($)
- The on-demand hourly rate used in the calculation, measured in $. Starts at 0.192 $ so you have a working example on load.
- Reserved hourly rate ($)
- The reserved hourly rate used in the calculation, measured in $. Starts at 0.116 $ so you have a working example on load.
- Upfront payment ($)
- The upfront payment used in the calculation, measured in $. Starts at 0 $ so you have a working example on load.
- Commitment term (years)
- The commitment term used in the calculation, measured in years. Starts at 1 years so you have a working example on load. Accepted range: 1–3 years.
- Expected utilization (%)
- The expected utilization used in the calculation, measured in %. Starts at 90 % so you have a working example on load. Accepted range: 1–100 %.
Results
- Total savings over term
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Savings percentage
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- On-demand total cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Reserved total cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Break-even utilization needed
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
What utilization number should I actually enter?
Use the minimum sustained usage you're confident about, not your peak or average — pull 90 days of CloudWatch/Monitoring data on the specific instance family and region you're committing to. Committing based on peak-season traffic that doesn't hold up the rest of the year is the most common way reservations end up costing more than on-demand.
Are savings plans better than standard reserved instances?
Compute savings plans apply the discount automatically across any instance family, size, OS, or region in exchange for committing to a dollar-per-hour spend rather than a specific instance, offering similar discounts (typically within a few percentage points) with much more flexibility. Standard RIs are only worth choosing over savings plans when you get an instance-size-flexibility or capacity-reservation guarantee that a savings plan doesn't provide.
Why is the 3-year discount so much bigger than 1-year?
The provider is pricing in the time value of your commitment and locking in demand further out, so a 3-year all-upfront term often prices near 60-72% off on-demand versus 30-40% for 1-year no-upfront. Only take the 3-year term for genuinely stable baseline workloads — architecture and instance-family needs change more than teams expect over three years.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
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Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Reserved vs On-Demand Cloud Savings Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/reserved-vs-on-demand-savings
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/reserved-vs-on-demand-savings" target="_blank" rel="noopener">Reserved vs On-Demand Cloud Savings Calculator — RevenueLab</a> (2026).</p>
Source: [Reserved vs On-Demand Cloud Savings Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/reserved-vs-on-demand-savings) (2026).