Planner Results
Annual On-Demand Cost
$0.00
Annual Reserved Cost
$0.00
Annual Savings
$0.00
Savings Percentage
0.00%
Total Term Savings
$0.00
Break-Even Usage
0.00%
Effective Reserved Hourly Rate
$0.0000
Unused Reservation Cost
$0.00
| Metric | Value |
|---|
Calculator Inputs
Use this planner to compare on-demand compute spend with reserved commitments across payment options, terms, utilization patterns, and expected workload growth.
Cost Comparison Graph
Example Data Table
| Parameter | Example Value | Explanation |
|---|---|---|
| Instances | 20 | Planned virtual machines needing compute coverage. |
| Hours per Month | 730 | Full monthly runtime for always-on workloads. |
| Utilization | 85% | Expected real usage of reserved capacity. |
| On-Demand Rate | $0.24/hour | Current pay-as-you-go compute rate. |
| Reserved Discount | 38% | Rate reduction from chosen reservation plan. |
| Coverage Ratio | 75% | Share of demand planned under reservation. |
| Monthly Growth | 1.2% | Expected increase in compute demand over time. |
| Overhead | $45/month | Administrative cost for commitment tracking. |
Formula Used
Demand Hours = Instances × Hours per Month × Utilization × (1 + Monthly Growth)n
Reserved Hours = Demand Hours × Coverage Ratio
On-Demand Cost = Demand Hours × On-Demand Hourly Rate
Reserved Rate = On-Demand Rate × (1 − Reserved Discount)
Mixed Cost = (Reserved Hours × Reserved Rate) + (Uncovered Hours × On-Demand Rate) + Monthly Overhead
Term Savings = Total On-Demand Term Cost − Total Reserved Term Cost
Break-Even Utilization = Reserved Rate ÷ On-Demand Rate, adjusted for overhead and upfront effect
This planner also estimates present value impact by discounting future monthly savings using the selected cost of capital.
How to Use This Calculator
- Enter the number of instances and average hours used monthly.
- Set expected workload utilization and future monthly growth.
- Provide the current on-demand hourly rate.
- Choose the expected reservation term and payment option.
- Enter the discount percentage offered by the reserved plan.
- Set the coverage ratio to reflect how much demand you want reserved.
- Add any monthly operational overhead for managing commitments.
- Click Calculate Plan to view savings, break-even usage, and term cost comparisons.
- Review the graph for monthly trend behavior.
- Export the results in CSV or PDF format when needed.
Frequently Asked Questions
1) What does this planner calculate?
It compares on-demand spending against reserved commitments. It estimates annual cost, total term savings, effective reserved rate, unused reservation cost, and a break-even usage threshold.
2) Why is utilization important?
Reserved capacity saves money only when used enough. Lower utilization means more idle commitment and weaker savings. High utilization generally improves reservation value.
3) What is coverage ratio?
Coverage ratio is the share of demand you plan to reserve. A 75% ratio means you reserve three quarters of expected workload hours.
4) How is break-even usage interpreted?
It shows the usage level where reserved and on-demand economics become similar. Above that threshold, reservations usually generate better savings.
5) Why include monthly growth?
Demand often changes over time. Growth helps model how future compute hours affect reservation value, uncovered usage, and long-term savings.
6) Does this include financing impact?
Yes. The planner uses a discount rate to estimate present value of savings. That helps compare upfront and non-upfront payment structures more fairly.
7) What does unused reservation cost mean?
It estimates money tied to reserved hours that are not actually consumed. It highlights risk from overcommitting relative to real usage.
8) When should I prefer a shorter term?
Choose a shorter term when workload volatility is high, pricing is uncertain, or architecture changes may reduce future usage needs.