| Spot Instance | On-demand Instance |
| With Spot Instance, customers can purchase compute capacity with no upfront commitment at all. | With On-demand Instance, users can launch instances at any time based on the demand. |
| Spot Instances are spare Amazon instances that you can bid for. | On-demand Instances are suitable for the high-availability needs of applications. |
| When the bidding price exceeds the spot price, the instance is automatically launched, and the spot price fluctuates based on supply and demand for instances. | On-demand Instances are launched by users only with the pay-as-you-go model. |
| When the bidding price is less than the spot price, the instance is immediately taken away by Amazon. | On-demand Instances will remain persistent without any automatic termination from Amazon. |
| Spot Instances are charged on an hourly basis. | On-demand Instances are charged on a per-second basis |
