Managed Database Cost Calculator
The managed-DB bill is not one number. Four providers, four different ways to bill the same PostgreSQL instance. AWS RDS doubles your compute the moment you check "Multi-AZ." Aurora throws in the standby for free but bills storage by the GB plus every million I/O. Cloud SQL and Azure DB sit somewhere in between — and all of them quietly charge for backup retention once you exceed one copy. This calculator models AWS RDS, Amazon Aurora, Google Cloud SQL, and Azure Database for MySQL/PostgreSQL side by side: compute, storage, provisioned IOPS, Multi-AZ HA, read replicas, backup retention, and committed-use discounts. No sales fluff — 2026 list prices.
📐 Database Configuration
Pick an engine, instance size, deployment topology, and storage profile. The engine models all four providers against the identical workload so the comparison is apples-to-apples. Prices are on-demand list rates in each provider's primary US region unless a region is selected.
📋 Managed DB Pricing Reference (2026 list prices)
On-demand hourly compute for the instance tiers used. GCP = us-central1, Azure = East US, AWS = selected region (us-east-1 baseline). Storage is per-GB-month. IOPS is RDS io1 only. Multi-AZ behavior and backup billing differ per provider — see notes.
| Tier | RDS $/hr | Aurora $/hr | Cloud SQL $/hr | Azure DB $/hr |
|---|---|---|---|---|
| 2 vCPU · 8 GB | $0.171 | $0.160 | $0.186 | $0.165 |
| 4 vCPU · 16 GB | $0.342 | $0.320 | $0.372 | $0.330 |
| 8 vCPU · 32 GB | $0.684 | $0.640 | $0.744 | $0.660 |
| 16 vCPU · 64 GB | $1.368 | $1.280 | $1.488 | $1.320 |
| 32 vCPU · 128 GB | $2.736 | $2.560 | $2.976 | $2.640 |
| 64 vCPU · 256 GB | $5.472 | $5.120 | $5.952 | $5.280 |
Storage: RDS gp3 $0.115/GB-mo · Aurora $0.10/GB-mo (+$0.20 per 1M I/O) · Cloud SQL SSD $0.17/GB-mo · Azure Premium SSD $0.115/GB-mo. RDS io1 $0.125/GiB-mo + $0.10 per provisioned IOPS-mo (Single-AZ). Backup: RDS charges $0.095/GB-mo for retained backups beyond the first DB-size copy (modeled at 10% daily change); Aurora/Cloud SQL/Azure include backup free up to 100% of storage. Multi-AZ: RDS/GCP/Azure bill a standby instance (compute ×2); Aurora's standby is included. Source: AWS RDS pricing pages, verified 2026-09-23 in us-east-1. Verify against your region.
The Bill Nobody Reconciles Until the Finance Ticket Lands
Managed databases are the quietest line item in the cloud bill — until the same PostgreSQL instance that costs $380/month on one provider costs $610 on another for identical throughput. The spread isn't margin noise. It's four structurally different pricing models that each hide a different tax. This calculator surfaces all four at once so you can see exactly where the money diverges.
1. Compute — and the Multi-AZ Doubling Trap
On AWS RDS, checking "Multi-AZ" does not buy you redundancy for free. It spins up a synchronous standby in a second AZ and bills it as a full second instance. Your 4 vCPU instance at $0.342/hr becomes $0.684/hr the instant you tick the box — $500/month in compute alone, before storage. Google Cloud SQL regional HA and Azure zone-redundant HA do the same: you pay for the standby. Amazon Aurora is the exception — its standby shares the same distributed storage volume, so Multi-AZ adds zero compute. For a single HA instance, that single difference is often a $200–400/month swing between Aurora and RDS at the same size.
2. Storage — gp3 vs io1 vs Aurora's GB + I/O
General Purpose SSD is cheap everywhere: RDS gp3 at $0.115/GB-month, Cloud SQL SSD at $0.17, Azure Premium SSD at $0.115. At 500 GB that's $58–85/month — negligible next to compute. The trap is provisioned IOPS on RDS io1: $0.125/GiB-month plus $0.10 per provisioned IOPS-month (Single-AZ). Provision 12,000 IOPS on a 200 GB volume and the IOPS line ($1,200/month) dwarfs the storage line ($25/month) by 48×. Aurora bills storage at $0.10/GB-month but then layers $0.20 per million I/O requests — invisible until you have a write-heavy workload. A million-row bulk insert can quietly cost more in I/O than the instance does in compute.
3. Backup Retention — The RDS-Only Surprise
Here's the asymmetry nobody warns you about: RDS is the only one of the four that bills retained backups. AWS gives you backup storage free up to 100% of your database size — i.e., exactly one copy. Push retention to 7 days and, assuming ~10% daily change, you're now paying for ~0.6 extra DB-sizes of backup at $0.095/GB-month. On a 500 GB database that's ~$28/month; on a 2 TB database at 30-day retention it's north of $500/month — a line item that simply does not exist on Aurora, Cloud SQL, or Azure DB, all of which include automated backups up to 100% of storage for free. If backup cost shows up as your third-largest component, that's an RDS tell.
4. Read Replicas — Storage Shared or Not
Read replicas are where the four diverge again. A Cloud SQL or Azure read replica is a whole second instance: you pay compute and storage again. An RDS read replica is the same. Aurora replicas share the cluster storage volume — you pay only for the replica's compute, never a second copy of the data. At 3 read replicas on a 1 TB database, that storage-sharing difference alone is ~$330/month (3 × 1 TB × $0.115) that Aurora doesn't charge. For read-heavy scale-out architectures, Aurora's storage model compounds in your favor.
5. Committed-Use Discounts — The Real Lever
All four providers reward commitment. RDS and Aurora 1-year No-Upfront reservations land around 35% off compute; 3-year around 60%. Cloud SQL committed-use discounts (1-yr ~45%, 3-yr ~64%) and Azure reserved instances (1-yr ~42%, 3-yr ~61%) are in the same ballpark. The catch: reservations apply to compute only — storage, IOPS, and backup are always on-demand. So a 3-year RDS commitment on an io1-heavy, backup-heavy workload saves less than it looks, because the discounted compute is a smaller fraction of the total bill. This calculator applies the discount to compute and leaves the rest at list, which is exactly how the providers bill it.
Who Should Care Most
| Profile | Typical Monthly Bill | What This Calculator Reveals |
|---|---|---|
| Startup, single AZ, 1 instance | $120–300/mo | Compute dominates. RDS vs Cloud SQL vs Azure are within ~10% — pick on ecosystem, not price. Aurora's standby-free Multi-AZ only matters once you add HA. |
| Production, Multi-AZ, 1 replica | $600–1,400/mo | Aurora pulls ahead on HA (no standby tax) and replica storage sharing. RDS backup retention + io1 IOPS are the sneaky lines. Cloud SQL/Azure sit between. |
| Read-heavy SaaS, 2–3 replicas | $1,500–4,000/mo | Aurora's shared-storage replicas save $300–700/mo vs RDS/Cloud SQL/Azure, which each bill replica storage. The gap widens with storage size and replica count. |
| Write-heavy, io1 + long retention | $2,000–8,000/mo | RDS io1 IOPS + backup retention can rival compute. Aurora's per-I/O model may be cheaper or pricier depending on write volume — model it, don't guess. |
Pricing Basis, Sources & Assumptions
Every rate on this page is a published vendor list price — no negotiated discounts, private pricing, or credit offsets. Totals are in USD and exclude tax. Rates were last checked against the sources below on .
| Pricing input | Basis used on this page |
|---|---|
| Region | us-east-1 (N. Virginia) unless a region is selected — the selector applies published regional multipliers for Amazon RDS and Aurora. The cross-provider table quotes each vendor's own published US list price (AWS, Google Cloud, Microsoft Azure). |
| Currency | USD — on-demand list price, tax excluded |
| Last checked | — three list-price errors were corrected on this date: RDS gp3 storage $0.138 to $0.115 per GiB-month, RDS io1 storage $0.200 to $0.125 per GiB-month, and RDS io1 provisioned IOPS $0.065 to $0.10 per IOPS-month (us-east-1, Single-AZ). Cross-provider instance rates are carried from the linked vendor price lists — re-check before committing spend. |
Modelling assumptions
- 730 hours per month. On-demand list price unless a commitment term is selected; Multi-AZ topology doubles instance hours.
- Storage is billed per GiB-month by class: RDS gp3 $0.115, RDS io1 $0.125, Aurora $0.10, Cloud SQL SSD $0.170, Azure Premium SSD $0.115. io1 provisioned IOPS is billed at $0.10 per IOPS-month on top of storage; snapshots and backups beyond the first copy at $0.095 per GiB-month.
- Backup storage is modelled with a 10% daily change rate, so retained copies accumulate over the retention window.
- Read replicas are billed as additional instances at the same rate. Monthly egress to the internet starts at $0.09/GB with the first 100 GB free.
Known limitation: io1 rates here are Single-AZ list prices. AWS bills io1 in Multi-AZ at $0.25 per GiB-month and $0.20 per IOPS-month, and this model does not scale the storage rate by topology — so a Multi-AZ io1 configuration is understated. - The $/hr table is a comparable-class table, not a price list: instance sizes are matched by vCPU and memory across engines, so engines without a 1:1 match are approximated.
What this model excludes
- License-included engines (SQL Server, Oracle) and their licence multipliers.
- Aurora I/O charges, Performance Insights paid tier, and Extended Support surcharges.
- Reserved Instance and Savings Plan effective rates beyond the discount shown in the commitment selector; io2 Block Express provisioned IOPS.
- Dedicated Log Volumes, tax, credits, and private pricing agreements.
Sources
- AWS (2026). "Amazon RDS for PostgreSQL Pricing." On-demand instance hours, gp3 and io1 storage, provisioned IOPS, and backup storage rates. aws.amazon.com
- AWS (2026). "Amazon Aurora Pricing." Aurora instance hours, storage, and I/O charges. aws.amazon.com
- Google Cloud (2026). "Cloud SQL Pricing." Cloud SQL instance and storage rates used in the cross-provider comparison. cloud.google.com
- Microsoft Azure (2026). "Azure Database for PostgreSQL Pricing." Flexible Server compute and storage rates used in the cross-provider comparison. azure.microsoft.com
- AWS (2026). "Storage Types for Amazon RDS." gp3 baseline IOPS and throughput, and io1 allocation limits. docs.aws.amazon.com
Vendor list prices change without notice — re-check the linked pages before committing spend. jslet takes no vendor sponsorship and carries no affiliate links; see about.