How Much Can You Save with Guaranteed Commitments vs. Native AWS RI and SP?

AWS Reserved Instances (RIs) and Savings Plans (SPs) can cut compute costs by 30–40% compared to on-demand pricing. Most enterprise and FinOps teams already know this. And yet, a significant share of cloud workloads still run on-demand, year after year, paying full price.

The reason isn't a lack of awareness. It's a structural risk problem. Native commitments require you to forecast accurately over a 1- or 3-year horizon, lock in capital — sometimes tens of thousands of dollars upfront — and accept that if usage drops, the unused spend is simply lost.

For any team navigating active growth, architectural changes, or workload evolution, those conditions are genuinely difficult to meet.

The result is a familiar compromise: either commit and risk stranded costs, or stay on-demand and leave real savings unrealized.

Guaranteed Commitments — available through Wave via your Alphaus-partnered MSP — resolve this through a different mechanism. Rather than forcing a choice between savings and flexibility, they deliver committed discount rates with a built-in money-back guarantee: if your actual usage falls below the committed amount, the unused portion is refunded. Your costs can never exceed on-demand pricing.

This article breaks down exactly how much you save under each model — at full utilization, at partial utilization, and the precise crossover point where the guarantee shifts from a nice-to-have into the financially superior choice.

Guaranteed Reserved Instance (GRI) is the counterpart to AWS's native Reserved Instance. It delivers a committed discount rate with a refund guarantee on unused savings after the minimum lock-in period.

Guaranteed Savings Plan (GSP) is the counterpart to AWS's native Compute Savings Plan. Both are no-upfront, flexible plans — the difference is that GSP guarantees your savings even if your actual usage drops during the commitment period.

Both carry a Risk Premium — the cost of the guarantee — calculated as a percentage of your realized monthly savings, not a flat fee. If usage drops and savings decrease, the premium decreases proportionally. If savings reach zero, no premium is charged.

A mid-to-large enterprise running 100 x EC2 m5.xlarge instances in Tokyo at full capacity will save more per month with a 1-Year Native Compute SP ($6,717 / 37.1%) than a 30-Day Guaranteed Commitments (GSP) ($3,621 / 20.0%) — but that advantage only holds if workload usage stays perfectly stable for the entire 12 months, which is the best-case scenario for native commitments and rarely the reality.

The 30-Day Guaranteed Commitments Plan charges a 50% Risk Premium on top of the native SP rate — that's the cost of flexibility and downside protection. If your workload runs unchanged at full capacity for the entire 12 months, the native SP wins on raw monthly savings by $3,322.96. The question every team should ask: How confident are you that nothing will change in the next 12 months?

The table below shows what each plan actually costs at different utilization levels across the same 100-instance fleet. Native SP charges the same $11,388 regardless — GSP adjusts with your actual usage and refunds the unused portion.

Below that threshold, the 30-Day GSP becomes cheaper in absolute terms than a 1-Year Native Compute SP — even though the native SP has the deeper headline discount. Any workload that dips below 80% utilization at any point during the year is in GSP territory.

For a fleet that starts at 80% utilization for 6 months then scales down to 50% for the remaining — a common pattern after a product launch or project completion:

The Guaranteed Commitments saves more over the year than the native SP — even though the native SP has a higher headline discount — purely because the guarantee absorbs the underutilization in the back half of the year.

The comparison sharpens considerably when moving from Savings Plans to Reserved Instances. Native RIs involve larger upfront payments and longer lock-in periods — which means the cost of being wrong is higher, and the value of the guarantee becomes more significant.

At 80% coverage and 70% utilization, a 100-instance EC2 m5.xlarge fleet on a 1-Year Guaranteed Commitments saves more per month against on-demand pricing and 1-Year Native RI No Upfront.

At the 70%/80% baseline native commitment may look better,but the question isn’t about who saves more, the question is what happens when utilization drops further.

Below 80% utilization threshold, the Guaranteed Commitments becomes cheaper in absolute terms than a 1-Year Native RI No Upfront — despite the native RI's deeper headline discount. This is a higher and earlier crossover than most teams expect.

For the same 100-instance fleet running at 80% utilization for 6 months then scaling to 50% for the remaining 6:

The Guaranteed Commitments saves more over the year than the native RI — again, because the guarantee refunds the underutilization in the back half while the native RI charges the full commitment regardless.

This scenario reflects the reality most enterprise teams face — a mixed compute and database footprint that a single native Savings Plan cannot fully cover.

An enterprise running 80× EC2 m5.large app servers alongside 40× RDS db.r5.large instances on a combined 1–Year Guaranteed Commitments covers both services under a single plan with a unified refund guarantee — while the equivalent native approach requires a separate 1–Year Compute SP for EC2 and an RDS Reserved Instance carrying $40,400 in upfront costs, each with its own lock-in and no protection if any database is resized or retired mid-term.

At full utilization, the native combination saves $816 more per month — but only if nothing changes. The native approach splits coverage across two separate plans: a Compute SP for EC2 and a Reserved Instance for RDS, each with its own commitment, its own lock-in, and no refund if either workload changes mid-year.

That's two plans to manage, two risk exposures to track, and two points of failure if either customer workload shifts. Under Guaranteed Commitments, both services run under a single plan with a unified refund guarantee — so if your database footprint shrinks or your app servers scale down, the proportional savings loss is refunded rather than absorbed.

For a mixed EC2 + RDS workload at 100% coverage, Guaranteed Commitments leads at 80% utilization baseline and extends that advantage at every lower level. Database workloads in particular fluctuate during product cycles, data migrations, and team restructuring—making Guaranteed Commitments the structurally stronger choice for most enterprise environments.

Native AWS plans carry no Risk Premium — the full commitment risk is held by the customer, with no refund if usage drops.

Two things worth noting: the 30-Day GSP precisely matches the 1-Year AWS Compute SP at 20% effective discount — with only a 30-day commitment instead of 12 months. And the 1-Year Guaranteed Commitments outperforms the 1-Year AWS Compute SP on effective discount (26.8% vs. 20%) while adding a full refund guarantee.

Guaranteed Commitments are available to enterprise end users through MSPs operating on Ripple. If you're working with an Alphaus-partnered MSP, the starting point is activating Guaranteed Commitments through Wave — the client-facing commitment management portal where you can review AI-recommended commitment plans, purchase GRI or GSP coverage, and track your utilization and savings in one place.

No upfront capital required. No multi-year lock-in. If savings go negative, the unused portion is refunded.

Calculate your potential savings → Explore the Ripple Guaranteed Commitment Savings Simulator