Understanding cloud egress costs

Egress is the data your cloud sends out. For many products, egress is the “silent” line item that grows with usage. This guide helps you estimate egress quickly and avoid common surprises.

1) Identify what kind of transfer you have

• Internet egress: data leaving your provider to end users.
• Cross-region transfer: replication, multi-region reads, DR traffic.
• CDN bandwidth: edge delivery (may be priced separately from origin egress).

2) Pick the right unit

Billing is often in decimal GB/TB, while OS tools might show GiB/TiB. Convert before estimating costs. Use the Units Converter if you’re unsure.

3) Estimate GB per month (quick methods)

• From analytics: use your CDN/origin dashboards for “bytes sent”.
• From API volume: requests/day × average response KB → GB/month (use the API tool).
• From throughput: Mbps × utilization × time → GB/month (use Units Converter).

4) Model cost with simple assumptions first

Start with “GB/month × $/GB”. You can refine later for tiering and free allowances. Tools: Egress, CDN bandwidth, cross-region.

Common pitfalls

• Tiered pricing: your average $/GB changes as traffic grows.
• Double counting: CDN bandwidth may not equal origin egress.
• Replication direction: some services bill only outbound, others have nuances.