Data sources & methodology

Data sources

All prices are collected from each cloud’s official pricing API. Nothing is entered by hand.

• AWS — Price List Bulk API (per-region offer files)
• Azure — Retail Prices API
• GCP — Cloud Billing Catalog API
• Exchange rate (USD→KRW) — for display only, refreshed daily (currently $1 = ₩1,376.6)

Collection and validation

Prices are collected automatically once a day. If a run looks abnormal compared to the previous day (many prices swinging ±30%, a sharp drop in item count), we treat it as a collector error and hold the update — a safeguard against showing corrupted data. The “prices collected” date on screen is the last healthy collection.

How estimates are computed

• Monthly cost = hourly price × 730 hours (the convention shared by all three official calculators)
• VM auto-matching: we pick the cheapest instance that satisfies both the requested vCPU and RAM (ties go to fewer vCPUs). The selected instance is always shown in the estimate — we never hide what the comparison is based on.
• Burstable instances (AWS t-series, Azure B-series, GCP E2 shared-core) can be included or excluded as an option.
• Storage = capacity × GB-month rate; traffic = cumulative tiered calculation with free allowances applied.

Comparison basis (unified for fairness)

• Linux on-demand list prices, shared tenancy, current-generation instances only.
• x86 only (ARM — AWS Graviton, GCP T2A — excluded: comparing identical specs across architectures would not be fair).
• Block storage compares the three general-purpose SSDs: AWS gp3 · GCP Balanced PD · Azure Premium SSD v2 (baseline performance included in the price).
• Object storage uses the standard tier, first pricing band (up to 50TB).
• Outbound traffic is unified on internet routingacross all three: GCP Standard network tier, Azure Routing Preference: Internet, AWS default. (GCP’s Premium tier prices depend on the destination, so a single comparison is not possible.)

Limitations — what this estimate does not tell you

• Commitment discounts (Savings Plans, CUD, RI), free tiers, and negotiated discounts are not reflected — your actual bill may be lower.
• Extra storage IOPS, API request counts, snapshots, load balancers, and other add-on charges are not included.
• Azure coverage is limited to four main series (B/Dsv5/Esv5/Fsv2), so matching options may be narrower.
• These estimates are meant for structural comparison and ballparking, not as a basis for contracts or billing.