Savings Plan Calculator

Size an AWS Savings Plan hourly commitment, then see covered spend, on-demand overflow, waste and net monthly saving.

About Savings Plan Calculator

A Savings Plan applies discounted rates to usage until your hourly dollar commitment is exhausted, and everything above it falls back to on-demand. Because usage is consumed at the discounted rate, an hourly commitment buys roughly commitment ÷ (1 − discount) worth of on-demand-equivalent usage — and any commitment you do not consume in an hour is simply lost, which is why utilisation matters as much as coverage. Commitments are billed hour by hour and unused dollars never roll over, so over-committing turns a discount into a surcharge; sizing to your steady-state trough is the standard safe play.

Formula

Savings Plan

discounted need = on-demand spend × (1 − discount); covered = min(commitment, discounted need); overflow at on-demand = (discounted need − covered) ÷ (1 − discount).

commitment: Dollars per hour you promise to spend for 1 or 3 years
discount: Savings Plan rate reduction against on-demand list price
discounted need: Your usage repriced at Savings Plan rates

Worked example

With the default values below, Savings Plan Calculator returns Monthly Cost With the Plan of $4,490.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Hourly commitmentminimum 0 USD/hour: 5 USD/hour
On-demand equivalent spend per hourminimum 0 USD/hour: 8 USD/hour
Savings Plan discount vs on-demandaccepts 0–90 %: 27 %
Hours in the billing monthaccepts 0–744 hours: 730 hours
Plan typeone of Compute Savings Plan — any region, family, Fargate and Lambda, EC2 Instance Savings Plan — one family in one region: Compute Savings Plan — any region, family, Fargate and Lambda

Results

Monthly Cost With the Plan: $4,490.00
Committed Spend (billed regardless): $3,650.00
Usage Billed at On-Demand: $840.00
Monthly Saving vs All On-Demand: $1,350.00
Commitment Utilisation: 100.0%
Flexibility Trade-off: Portable across regions, families, Fargate and Lambda at a smaller discount

Step by step

1Values used
2Savings Plan
3Monthly Cost With the Plan= 4,490.00
4Committed Spend (billed regardless)= 3,650.00
5Usage Billed at On-Demand= 840.00
6Monthly Saving vs All On-Demand= 1,350.00
7Commitment Utilisation= 100.0
8Flexibility Trade-off= Portable across regions, families, Fargate and Lambda at a smaller discount

Assumptions and limits

The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Savings Plan calculated?

discounted need = on-demand spend × (1 − discount); covered = min(commitment, discounted need); overflow at on-demand = (discounted need − covered) ÷ (1 − discount). A Savings Plan applies discounted rates to usage until your hourly dollar commitment is exhausted, and everything above it falls back to on-demand. Because usage is consumed at the discounted rate, an hourly commitment buys roughly commitment ÷ (1 − discount) worth of on-demand-equivalent usage — and any commitment you do not consume in an hour is simply lost, which is why utilisation matters as much as coverage.

Why does Savings Plan matter?

Commitments are billed hour by hour and unused dollars never roll over, so over-committing turns a discount into a surcharge; sizing to your steady-state trough is the standard safe play.

What values do I need to enter?

This calculator takes 5 inputs: Hourly commitment, On-demand equivalent spend per hour, Savings Plan discount vs on-demand, Hours in the billing month, Plan type. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

Should I aim for 100% coverage?

No. Coverage and utilisation pull against each other: commit to your trough of steady usage and let spiky or short-lived capacity run on-demand or on Spot. Most FinOps teams target high utilisation (near 100%) and accept coverage somewhere in the 70–85% range.