Cloud tiered pricing is a rate per unit that falls once usage within a billing period crosses published thresholds, as for object storage or data transfer to the internet. Alongside it, Google Cloud's sustained use discounts lower the price of some Compute Engine resources that run for much of the month. Both apply with nothing bought, and the counters restart with every billing period, daily for Google SKUs aggregated per day. For the bill, the same quantity costs a different rate per unit in different months and accounts, depending on what usage was counted together.
How it works
Under tiered pricing each rate applies only to the units within its tier: the first units pay the first tier's rate, and only the units above a threshold pay the lower one. A line's rate per unit is therefore an average that depends on the total quantity. Two questions settle it: which usage is counted together, and when does the counter restart? How quantity and rate form a line is covered in usage, rates and line items on a cloud invoice.
AWS
Amazon S3 Standard is priced per month in three tiers: the first 50 TB, the next 450 TB and everything over 500 TB, each per GB. Data transfer to the internet is tiered too, and the tier follows from the sum across several services, among them Amazon EC2, Amazon S3 and Amazon RDS. With consolidated billing, AWS treats all accounts in an organisation as one account for volume tiers: the tier follows from the combined usage, and each member account receives a share of the volume discount based on its usage. In the Cost and Usage Report, pricing_rate_code identifies the combination of product, offer and pricing tier.
Azure
Internet egress is tiered per source continent: the first 100 GB a month free, then tiers for the next 10 TB, 40 TB, 100 TB and 350 TB, with Microsoft counting 1 TB as 1,000 GB. The Azure Retail Prices API returns a separate record per tier with tierMinimumUnits, the minimum quantity from which the price applies; in the cost details, EffectivePrice already reflects the tier. Under a Microsoft Customer Agreement, usage is aggregated monthly per billing profile, and tiered prices are set per billing profile, never across several.
Google Cloud
Google tiers per SKU. The pricing export to BigQuery lists the tiers in list_price.tiered_rates with start_usage_amount and a price, and aggregation_info sets what is counted: per Cloud Billing account (ACCOUNT) or project (PROJECT), per day (ONE_DAY) or month (ONE_MONTH). Counters restart at midnight US Pacific time. Tiers never span Cloud Billing accounts, even within one organisation or legal entity. In the standard export, price.tier_start_amount gives the lower bound of a line's tier.
Sustained use discounts
Compute Engine grants sustained use discounts (SUDs) on resources that run for more than a quarter of the billing month and receive no other discount. Eligible are the vCPUs and memory of the N1, N2, N2D, C2, M1 and M2 series, sole-tenant nodes and GPUs attached to N1 machines. The discount grows in steps at 25, 50, 75 and 100 per cent of the month to a maximum of 20 per cent (N2, N2D, C2) or 30 per cent (N1, M1, M2, f1-micro, g1-small). Google combines usage per machine family and region within the account. Only Self-serve (Online) Cloud Billing accounts are eligible, and usage under committed use discounts, Spot VMs and preemptible VMs receives no SUDs. The discount arrives at month end as a credit with no cash value, shown in the export with credits.type = SUSTAINED_USAGE_DISCOUNT.
| Provider | Mechanism | Counted across | Restarts | In the data |
|---|---|---|---|---|
| AWS | tiers, such as S3 Standard and data transfer to the internet | the organisation under consolidated billing; several services for data transfer | month | pricing_rate_code |
| Azure | tiers, such as internet egress | billing profile (Microsoft Customer Agreement) | month | tierMinimumUnits, EffectivePrice |
| Google Cloud | tiers per SKU | Cloud Billing account or project | day or month, Pacific time | tiered_rates, aggregation_info, price.tier_start_amount |
| Google Cloud | sustained use discounts | machine family and region in the Cloud Billing account | month | credit SUSTAINED_USAGE_DISCOUNT |
What it means for your cost
A rate per unit is only final once the period's quantity has settled the tier, so a daily figure in mid-month is provisional. Any comparison of unit cost across accounts or months has to state whether tiers were counted together. On AWS an account's rate depends on the usage of the whole organisation; on Azure and Google the count stops at the boundary of the billing profile or Cloud Billing account. A new account structure can therefore change the rate with no change in usage (billing accounts and hierarchies).
SUDs do not appear as a lower rate but as a credit beside a line item at the full rate. A report that sums only cost shows eligible VMs without the discount; the cost after discount needs the credits as well (list, billed, effective and amortized cost). Because SUDs reach only usage with no other discount, a committed use discount on the same usage replaces the SUD, and the commitment's gain there is measured against the SUD rate (Google Cloud committed use discounts).
In FOCUS, tiered prices fall under PricingCategory Standard. The access tiers of storage classes such as S3 Intelligent-Tiering are not price tiers: they separate access patterns, not quantities (storage tiers and lifecycle). How the list price itself is formed is covered in on-demand pricing, and what data transfer costs in data transfer and egress.
Where it goes wrong
- Rate moves without more usage. Symptom: an AWS account pays more or less per GB than the month before for the same quantity. Cause: the tier follows from the usage of the whole organisation.
- New billing profile, higher price. Symptom: after a split, egress or storage cost rises with no extra usage. Cause: Azure sets tiered prices per billing profile, Google per Cloud Billing account.
- SUD looked for in the cost line. Symptom: N1 or N2 VMs appear at the full rate in a report. Cause: Google grants SUDs as a monthly credit, which a report without
creditsdoes not show. - No SUD despite constant load. Symptom: VMs run all month with no discount. Cause: the series is not on the list (E2 or N4, for instance), the account is not a Self-serve account, or a CUD already covers the usage.
- Project moved mid-month. Symptom: the SUD comes out lower than the month before at the same run time. Cause: in the new Cloud Billing account the count starts at zero, and both accounts receive separate SUDs.
Example
On 2026-10-16 Microsoft's bandwidth pricing page lists these rates for internet egress over the Microsoft Premium Global Network from North America and Europe, which includes Germany West Central, in US dollars per GB:
| Monthly quantity | Rate per GB |
|---|---|
| first 100 GB | free |
| next 10 TB | USD 0.087 |
| next 40 TB | USD 0.083 |
| next 100 TB | USD 0.07 |
| next 350 TB | USD 0.05 |
For resources with a 30 per cent maximum, Google documents that the four quarters of the month are charged at 100, 80, 60 and 40 per cent of the on-demand price; a resource running half the month thus receives an effective 10 per cent, one running all month 30 per cent.
Sources
Read on 2026-10-16. AWS Amazon S3 pricing, Amazon EC2 On-Demand pricing, data transfer, Effective billing date, account activity, and volume discounts, CUR 2.0 pricing columns; Microsoft Bandwidth pricing, Azure Retail Prices API, Ingest cost details data, Organize your invoice based on your needs; Google Cloud Sustained use discounts, VM instance pricing, Structure of pricing data export, Structure of standard data export; FinOps Foundation Pricing Category.