Commitment Savings Calculator
Value a spend commitment, counting commitment you do not use.
What this calculator does
Usage below the commitment is still billed at the commitment, so the shortfall shows as commitment not used and reduces the saving. Nothing about the agreement is assumed.
Inputs and what they mean
- Currency
- — Amounts are shown in the currency you pick. No exchange rate is applied..
- Usage per period, valued at on-demand prices
- — number value.
- Discount the commitment gives
- — The discount written into your agreement..
- Amount committed per period
- — number value.
- Periods in the term
- — number value.
- 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
Discounted cost = On-demand value × (1 − Discount); Billed = max(Discounted cost, Commitment); Saving = (On-demand value − Billed) × Periods
Worked example
$60,000 a month of usage under a $40,000 commitment at 20% off
Any part of the commitment you do not use is shown, not hidden.
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
Results depend entirely on the figures you enter and are rounded for display. They are for general information and education, not professional advice.
Reference: The Linux Foundation — Rate optimisation — FinOps Framework
Last reviewed:
Common questions
Formula, source and verification
Usage priced at the agreed discount, floored at the amount committed, compared with the on-demand value of the same usage.
The question it answers: Would this reservation, spend commitment or resizing plan actually save us money at the usage we really have?
The formula
Discounted cost = On-demand value × (1 − Discount); Billed = max(Discounted cost, Commitment); Saving = (On-demand value − Billed) × Periods
- V — On-demand value of usage
- (currency). What the covered usage would cost without the commitment.
- d — Discount
- (%). The discount written into the agreement.
- K — Commitment per period
- (currency). Minimum billed whether used or not.
- p — Periods
- (count). Periods in the term.
Units: Currency; percentages; periods.
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
Usage below the commitment is still billed at the commitment, so the shortfall shows as commitment not used and reduces the saving. Nothing about the agreement is assumed.
Assumptions built into the result
- Mathematical: The commitment is billed in full in every period of the term.
- 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 commitment discount is assumed.
Limitations
- Level usage across the term; it does not model a usage profile changing month to month.
- 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.
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