Answer “what would it save?” before the change request
Every cost change starts with the same question from someone who has to approve it. The What-If Simulator answers it against your real AWS inventory, not a spreadsheet of assumptions, and shows both the money and the carbon side of the decision.
The five scenarios
- Migrate every gp2 volume to gp3 at the same size — usually the safest saving in AWS.
- Delete idle and unattached resources — everything the inventory currently flags.
- Right-size one step down — every running EC2 instance moved one size smaller within its family, which is a quick way to size the prize before you look at utilization patterns one by one.
- Add capacity — 1 to 500 instances of a catalog type, priced in your most-used region, to budget for growth.
- Apply a 1-year Compute Savings Plan at a 28% discount on eligible compute.
Each result shows the monthly and annual cost change and the monthly change in estimated kgCO₂e, with the assumptions listed underneath and a CSV export for the change ticket.
Estimates, clearly labelled
Results use the same bundled price catalog as pricing analysis and the same model as the carbon estimates. They are designed to size a decision quickly; confirm the final figures with AWS before committing to a purchase.