Cloud Cost & FinOps
Spot Instance Savings Estimator
Enter on-demand hourly rate, spot discount percentage, and expected interruption rate to compute effective hourly cost, monthly savings, and break-even interruption tolerance.
No data is transmitted — everything runs locallyTool
Example — $0.48/hr on-demand · 70% spot discount · 5% interruption · 730h/mo
Spot Rate
$0.144/h
70% discount
Effective Saving
66.5%
accounting for interruptions
Monthly Saving
$233.02
vs full on-demand
Interruption Tax
$0.00
5% interruption rate cost
About this tool
Spot Instance Savings Estimator
The Spot Instance Savings Estimator computes effective spot savings adjusted for interruption rate, with break-even analysis and mixed fleet cost modeling.
• Calculate net savings from spot instances after accounting for interruption cost
• Determine the interruption rate threshold where spot becomes more expensive than on-demand
• Model mixed fleet cost: on-demand base + spot flex for burst workloads
• Justify spot adoption to engineering leadership with expected savings range
Affiliate disclosure
Developer-friendly cloud infrastructure. DigitalOcean provides cloud compute, networking, and managed databases with predictable pricing.
Use preemptible instances on DigitalOcean
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FAQ
What does this tool tell you?
The Spot Instance Savings Estimator computes effective spot savings adjusted for interruption rate, with break-even analysis and mixed fleet cost modeling.
What affects the result most?
Spot vs on-demand discount typically 60–90% — varies by instance family and AZ. Interruption risk: spot instance termination notice is 2 minutes for AWS, 30 sec for GCP. Effective monthly cost with interruption model: spot_price × (1 - interruption_rate) + on_demand × interruption_rate.
How should I use the result?
The calculation is deterministic — the same inputs always produce the same output — so the most useful workflow is to vary one input at a time and see which factor moves the result most. That tells you where to focus your attention before committing to a decision.
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