Reserved Capacity Savings Calculator
Compare reserved capacity with on-demand at the usage you expect.
In short
Compare reserved capacity with on-demand at the usage you expect.
Formula: On-demand cost = On-demand price × Hours × Instances × Coverage; Reserved cost = Upfront + Reserved price × Hours × Instances; Saving = On-demand cost − Reserved cost
What this calculator does
Both sides are priced at the user's own rates. Reserved capacity is charged for the whole term whether or not it is used, so unused coverage reduces the saving and can turn it negative — which the result says plainly.
Use it to turn Currency, On-demand price per hour, Reserved price per hour, Upfront payment (optional), and the other shown inputs into a checked result you can compare, copy, or rerun with different assumptions.
The page shows the formula, a numeric worked example, and the assumptions that affect this professional & industry calculation.
Inputs and what they mean
- Currency
- — Amounts are shown in the currency you pick. No exchange rate is applied..
- On-demand price per hour
- — Take this from your own bill or the provider's price page. No provider price is built in..
- Reserved price per hour
- — Take this from your own bill or the provider's price page. No provider price is built in..
- Upfront payment (optional)
- — Optional component. Leave at 0 to exclude it from the result..
- Hours in the term
- — number value.
- Instances reserved
- — number value.
- Share of those hours you actually use
- — Reserved capacity you do not use is still paid for..
- Price as of (optional)
- — The date you took these prices. It is shown with the result so the figure is never read as a current vendor price..
- Price source (optional)
- — Where the prices came from. Shown with the result..
How to use it
- Enter your own figures — the calculator never fills in a rate, price or benchmark for you.
- Press Calculate to see the result.
- Read the formula, variables, assumptions and source below the result before you rely on it.
Formula
On-demand cost = On-demand price × Hours × Instances × Coverage; Reserved cost = Upfront + Reserved price × Hours × Instances; Saving = On-demand cost − Reserved cost.
Inputs used: Currency, On-demand price per hour, Reserved price per hour, Upfront payment (optional), Hours in the term, Instances reserved, Share of those hours you actually use, Price as of (optional), and other shown inputs.
Edge handling: On-demand price per hour is required.; On-demand price per hour cannot be negative.; On-demand price per hour must be no more than 1000000000.; Reserved price per hour is required.; Reserved price per hour cannot be negative..
Worked example
Ten instances reserved for a year at full use
- Start with Currency: USD, On-demand price per hour: 0.192, Reserved price per hour: 0.121, Upfront payment (optional): 0, Hours in the term: 8760, Instances reserved: 10.
- Apply the method: On-demand cost = On-demand price × Hours × Instances × Coverage; Reserved cost = Upfront + Reserved price × Hours × Instances; Saving = On-demand cost − Reserved cost.
- Both prices and the upfront payment are yours; no discount percentage is assumed.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
- Inputs outside the supported range are rejected rather than forced into a result.
- The result depends on the values you enter for this reserved capacity savings calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Reference: The Linux Foundation — Rate optimisation — FinOps Framework
Last reviewed:
Common questions
Where does this formula come from?
FinOps Framework capability: rate optimisation — a commitment or reservation is evaluated by comparing what the same usage would cost at on-demand rates with what the commitment actually costs, including anything committed but unused. See the source link on this page.
What kind of calculation is this?
What the hours actually used would cost at on-demand prices, less the full cost of the reservation including hours paid for but not used. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
What are its limits?
Compares two prices the user entered; it does not model changing the fleet during the term. The result is only as current as the prices entered; a price taken months ago is not a current vendor price. Arithmetic over the figures entered — it cannot tell whether the usage or the rate card behind them is right.
How do I use the Reserved Capacity Savings Calculator?
Enter the required values for Currency, On-demand price per hour, Reserved price per hour, Upfront payment (optional), Hours in the term, and the other fields shown. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.
What formula does the Reserved Capacity Savings Calculator use?
On-demand cost = On-demand price × Hours × Instances × Coverage; Reserved cost = Upfront + Reserved price × Hours × Instances; Saving = On-demand cost − Reserved cost The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
Can the Reserved Capacity Savings Calculator be used for exact decisions?
Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.
Formula, source and verification
What the hours actually used would cost at on-demand prices, less the full cost of the reservation including hours paid for but not used.
The question it answers: Would this reservation, spend commitment or resizing plan actually save us money at the usage we really have?
The formula
On-demand cost = On-demand price × Hours × Instances × Coverage; Reserved cost = Upfront + Reserved price × Hours × Instances; Saving = On-demand cost − Reserved cost
- ro — On-demand price per hour
- (currency). From the user's own price page.
- rr — Reserved price per hour
- (currency). The rate in the user's reservation.
- U — Upfront payment
- (currency). Optional. Paid at the start of the term.
- h — Hours in the term
- (h). Length of the reservation.
- n — Instances reserved
- (count). How many are reserved.
- c — Coverage
- (%). Share of the reserved hours actually used.
Units: Currency; hours; counts; percentages.
What kind of calculation this is
Business input model. The answer depends on business figures only you can supply, such as your own costs, rates or volumes. No market or benchmark values are assumed for you.
Method
Both sides are priced at the user's own rates. Reserved capacity is charged for the whole term whether or not it is used, so unused coverage reduces the saving and can turn it negative — which the result says plainly.
Assumptions built into the result
- Mathematical: The reservation is paid for the whole term regardless of use.
- Mathematical: Every price is the one the user entered, in the currency they chose; no exchange rate is applied.
- Mathematical: Usage and prices cover the same period.
Figures this calculator will never guess for you
- No provider price, instance rate, storage rate or transfer rate is built in.
- No typical discount, saving or industry average is suggested.
- No typical reservation discount is assumed.
- No coverage level is assumed.
Limitations
- Compares two prices the user entered; it does not model changing the fleet during the term.
- The result is only as current as the prices entered; a price taken months ago is not a current vendor price.
- Arithmetic over the figures entered — it cannot tell whether the usage or the rate card behind them is right.
Source and version
- Standard or reference
- FinOps Framework — rate optimisation — FinOps Foundation (FinOps Framework capability: rate optimisation — a commitment or reservation is evaluated by comparing what the same usage would cost at on-demand rates with what the commitment actually costs, including anything committed but unused.)
- Published source
- The Linux Foundation — FinOps Framework
- Formula version
- Version 1
- Verification
- Reviewed against the cited source on
- How much weight the source carries
- Standards or government
- Applies to
- Currency
- Amounts stay in the currency you choose; no exchange rate is applied.
Cite this page
Free Calculator. (2026, September 16). Reserved Capacity Savings Calculator. https://freecalculator.tech/tools/reserved-capacity-savings-calculator
"Reserved Capacity Savings Calculator." Free Calculator, 16 Sept. 2026, https://freecalculator.tech/tools/reserved-capacity-savings-calculator.
Reserved Capacity Savings Calculator — Free Calculator, https://freecalculator.tech/tools/reserved-capacity-savings-calculator
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