Right-Sizing Savings Calculator
Compare today's resource cost with a proposed smaller size.
In short
Compare today's resource cost with a proposed smaller size.
Formula: Saving = (Cost today − Cost after resizing) × Resources × Months − One-off cost of the change
What this calculator does
A difference of two costs the user entered, extended over the resources and months, net of the one-off cost of making the change.
Use it to turn Currency, Current cost per resource per month, Cost per resource per month after resizing, Resources being resized, 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..
- Current cost per resource per month
- — number value.
- Cost per resource per month after resizing
- — number value.
- Resources being resized
- — number value.
- Months to count
- — number value.
- One-off cost of making the change (optional)
- — Optional component. Leave at 0 to exclude it from the result..
- 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
Saving = (Cost today − Cost after resizing) × Resources × Months − One-off cost of the change.
Inputs used: Currency, Current cost per resource per month, Cost per resource per month after resizing, Resources being resized, Months to count, One-off cost of making the change (optional), Price as of (optional), Price source (optional).
Edge handling: Current cost per resource per month is required.; Current cost per resource per month cannot be negative.; Current cost per resource per month must be no more than 1000000000000.; Cost per resource per month after resizing is required.; Cost per resource per month after resizing cannot be negative..
Worked example
24 instances halved in size for a year
- Start with Currency: USD, Current cost per resource per month: 280, Cost per resource per month after resizing: 140, Resources being resized: 24, Months to count: 12, One-off cost of making the change (optional): 0.
- Apply the method: Saving = (Cost today − Cost after resizing) × Resources × Months − One-off cost of the change.
- Both costs come from your own bill; no typical saving 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 right-sizing 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?
The monthly difference across the resources being resized, over the months counted, less the cost of making the change. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
What are its limits?
Assumes the smaller size performs; it says nothing about capacity headroom or risk. 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 Right-Sizing Savings Calculator?
Enter the required values for Currency, Current cost per resource per month, Cost per resource per month after resizing, Resources being resized, Months to count, 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 Right-Sizing Savings Calculator use?
Saving = (Cost today − Cost after resizing) × Resources × Months − One-off cost of the change 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 Right-Sizing 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
The monthly difference across the resources being resized, over the months counted, less the cost of making the change.
The question it answers: Would this reservation, spend commitment or resizing plan actually save us money at the usage we really have?
The formula
Saving = (Cost today − Cost after resizing) × Resources × Months − One-off cost of the change
- c0 — Cost today per resource per month
- (currency). From the user's own bill.
- c1 — Cost after resizing
- (currency). The price of the proposed size, from the user's own price page.
- n — Resources
- (count). How many are being resized.
- m — Months
- (month). Months counted.
- K — One-off cost of the change
- (currency). Optional. Engineering time, downtime or migration.
Units: Currency; counts; months.
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
A difference of two costs the user entered, extended over the resources and months, net of the one-off cost of making the change.
Assumptions built into the result
- Mathematical: The resized resource carries the same workload acceptably.
- 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 right-sizing saving is assumed.
Limitations
- Assumes the smaller size performs; it says nothing about capacity headroom or risk.
- 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). Right-Sizing Savings Calculator. https://freecalculator.tech/tools/right-sizing-savings-calculator
"Right-Sizing Savings Calculator." Free Calculator, 16 Sept. 2026, https://freecalculator.tech/tools/right-sizing-savings-calculator.
Right-Sizing Savings Calculator — Free Calculator, https://freecalculator.tech/tools/right-sizing-savings-calculator
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