Prices, bill drivers and 2026 rules
On-demand vs reserved instances vs savings plans vs spot: choosing a cloud pricing model
How on-demand, reserved instances, savings plans, committed-use discounts and spot capacity differ, how to size a commitment, and an illustrative break-even for a small business.
Public cloud sells the same server under different pricing models. On-demand costs the most per hour but commits you to nothing. Reserved instances, savings plans and committed-use discounts lower the hourly price in exchange for a one- or three-year commitment that you pay whether or not you use it. Spot (also called preemptible or low-priority) capacity is the cheapest but can be reclaimed by the provider at short notice. For most small businesses the best fit is: commit only to the servers you are confident will run all day, every day, for the whole term; keep everything else on demand; and use spot only for work that can be interrupted. In the illustrative example below, a one-year commitment breaks even if the server runs at least about 7½ months of the year.
This guide belongs to the pricing overview. For the arithmetic of a specific commitment use the commitment payback guide and the payback calculator. Sizing is in vCPU, RAM and instance pricing. Figures and discounts are illustrative.
The four models side by side
| Model | What you commit to | Price vs on-demand | Flexibility | Good fit |
|---|---|---|---|---|
| On-demand | Nothing; pay per second or hour | Baseline | Full: stop any time | New, variable or short-lived workloads |
| Reserved instance | A specific instance type (sometimes size-flexible) in a region, 1 or 3 years | Lower; deeper for 3 years and upfront payment | Low; some can be exchanged or resold | Steady servers you will not change |
| Savings plan / commitment to spend | A dollar amount of compute per hour, 1 or 3 years | Lower; usually a little less discount than the most specific reservation | Medium: applies across sizes or families | Steady total usage with changing server mix |
| Spot / preemptible | Nothing, but capacity can be reclaimed | Lowest, varies with demand | Interruptions at short notice | Batch jobs, testing, stateless workers |
Names and rules differ between providers. Some also apply automatic discounts for sustained use without a commitment. Read the current terms on the provider's pricing pages for the exact discount, the payment options (all upfront, partial upfront, no upfront) and whether a commitment can be changed or cancelled.
Break-even: how much of the year must the server run?
A commitment charges you for every hour of the term. On demand charges only for the hours used. The break-even utilisation is therefore committed price ÷ on-demand price.
Illustrative example: a server costs $0.20 an hour on demand. A one-year commitment with no upfront payment costs $0.125 an hour (37.5% lower).
- On demand for a full year: 8,760 × $0.20 = $1,752.
- Committed for a full year: 8,760 × $0.125 = $1,095. Saving: $657.
- Break-even: $0.125 ÷ $0.20 = 62.5% of the year, about 7½ months or 5,475 hours.
If you might switch the server off, shrink it or move provider within the year, the commitment may cost more than on demand. That is the main risk: an unused commitment is pure cost.
How to size a commitment
- Find your floor. Look at hourly usage over the past three to six months. The lowest level you never drop below is your steady floor.
- Commit below the floor. Covering 60–80% of the floor leaves room for change; this is a common rule of thumb, not a requirement.
- Prefer flexibility when the mix may change. A spend commitment that applies across instance families suits a business still right-sizing; a specific reservation suits a server that has been stable for a year.
- Choose term and payment deliberately. Three-year terms usually carry a bigger discount but tie you to the provider for longer. Paying upfront increases the discount but uses cash, and for tax purposes an upfront payment covering more than 12 months may need to be spread rather than deducted at once; ask your tax agent.
- Put renewal dates in the diary. Commitments expire and the price reverts to on demand. Check the renewal price shock guide for the same pattern on hosting plans.
Spot capacity: cheap, with conditions
Spot capacity suits work that can stop and restart: rendering, data processing, test environments, build servers and stateless web workers behind a load balancer with on-demand capacity as a base. It does not suit a single database server or a website on one server.
Illustrative example: a nightly data-processing job needs 4 servers for 3 hours. On demand at $0.20 an hour: 4 × 3 × 30 × $0.20 = $72 a month. On spot at an illustrative 70% discount ($0.06 an hour): 4 × 3 × 30 × $0.06 = $21.60, if the job tolerates being interrupted and retried. Spot prices move; check the price history the provider publishes.
Commitment discounts and non-hyperscale hosts
VPS, dedicated and managed hosting providers often give a discount for paying annually or for a 12–36 month term. The logic is the same: you trade flexibility for price. Before signing:
- check the price after the term, and whether it renews automatically;
- check what happens if you need to downgrade or leave early;
- check whether a promotional price applies only to the first term.
Contract rules for these terms are in hosting contract terms and renewals.
Frequently asked questions
Can I cancel a reserved instance or savings plan?
Generally not, though some reservations can be exchanged or sold, depending on the provider and type. Treat the commitment as a fixed cost for the whole term.
Do commitments apply in Australian regions?
Commitments are usually region-specific for reservations and broader for spend-based plans. Check whether the discount applies to the Sydney or Melbourne region you use.
Does a commitment fix the AUD price?
Not if you are billed in US dollars: the USD rate is fixed, but the AUD cost still moves with the exchange rate. See USD pricing and FX.
Is a three-year commitment risky for a small business?
It can be. Your business, software and the provider's newer instance types may change in three years. Many small businesses prefer one-year terms or spend-based plans for that reason.
Sources
- Australian Taxation Office — deductions for prepaid expenses and business expenses
- Australian Competition and Consumer Commission — unfair contract terms in small business contracts
- business.gov.au — managing cash flow and contracts
- Reserve Bank of Australia — exchange rates for USD-priced commitments
