Object Storage Cost Calculator: Capacity, Requests, Retrieval and Egress
Estimate a provider-neutral object storage bill from average stored capacity, API requests, archive or infrequent-access retrieval, and outbound data transfer. Enter the rates from your provider, contract, or invoice.
Usage and rate inputs
Storage is prorated using a 30-day billing month.
Rates must all use this same currency.
Capacity
Use average billable capacity, not only the end-of-period value.
Requests
Retrieval and outbound transfer
Enter zero for storage classes without retrieval fees.
Allowance for this calculation period; enter zero if none applies.
Tip: press Ctrl/⌘ + Enter to recalculate.
Estimated object storage cost
Enter valid inputs to calculate object storage cost.
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Worked example: 10 TB with requests, retrieval, and egress
For 10 TB stored over 30 days at 0.023 per GB-month, capacity costs 230. One million write requests at 0.005 per 1,000 add 5, and 10 million reads at 0.0004 per 1,000 add 4.
Retrieving 1 TB at 0.01 per GB adds 10. If 2 TB leaves the provider, a 100 GB allowance leaves 1,900 GB billable; at 0.09 per GB, egress adds 171. The total is 420 for the selected 30-day period. These are generic example rates, not a quote or a statement of any provider's current pricing.
Object storage cost formulas
Capacity in GB: entered capacity × decimal unit multiplier
Storage cost: average capacity in GB × price per GB-month × period days ÷ 30
Request cost: request count ÷ selected request billing unit × price per unit
Retrieval cost: retrieved GB × retrieval price per GB
Billable egress: max(0, outbound GB − free allowance GB)
Egress cost: billable egress GB × egress price per GB
Period total: storage + write requests + read requests + retrieval + egress
Annualized run rate: period total × 365 ÷ period days
All data units are decimal billing units: 1 GB = 1,000,000,000 bytes, 1 TB = 1,000 GB, and 1 PB = 1,000 TB. The 30-day storage proration is a scenario assumption; replace it with invoice-period data if your provider calculates average capacity, hourly usage, or calendar-month proration differently.
What belongs in an object storage estimate?
| Cost component | Input to collect | Common omission |
|---|---|---|
| Capacity | Average billable GB by storage class, including replicas where billed | Using month-end capacity for a workload that changed throughout the period |
| Requests | Operation counts mapped to the provider's request classes | Ignoring list, lifecycle, copy, multipart, or failed request charges |
| Retrieval | GB read from archive or infrequent-access classes | Treating retrieval as synonymous with internet egress |
| Egress | GB by destination and route after applicable allowances | Applying an internet rate to same-region, inter-region, or CDN traffic |
| Other services | Replication, transitions, inventory, monitoring, encryption keys, support, and tax | Assuming the four modeled components reproduce the complete invoice |
How to choose rates and usage
- Keep all inputs within the same account scope, region, storage class, and period.
- Use invoice exports or metering data for average stored bytes and request counts when available.
- Normalize provider request prices to the matching 1K, 10K, or 1M selector.
- Use the marginal rate for a proposed change, or a blended rate when reproducing an existing bill.
- Model different storage classes or pricing tiers separately, then add their totals.
- Validate the estimate against a recent invoice before making a migration or budget decision.
Retrieval and egress may both apply to the same bytes. An archive download can incur a storage-class retrieval fee and a separate network transfer fee. Check the source class, destination, region, and any provider-specific free-transfer rules.
Frequently asked questions
What costs are included in the object storage estimate?
The calculator includes average capacity, two request classes, retrieval, and outbound transfer after a free allowance. It does not automatically include lifecycle transitions, replication, inventory, monitoring, minimum-duration or early-deletion charges, taxes, support, or provider-specific tiers.
Are retrieval and egress the same charge?
No. Retrieval is commonly a storage-class fee for reading archived or infrequently accessed data. Egress is a network transfer fee. Depending on the service and route, the same bytes can incur both.
Should storage capacity use GB or GiB?
Use the unit shown by the provider. This calculator uses decimal GB, TB, and PB. If billing uses GiB, convert measured bytes to GiB before entering a normalized rate or adjust the per-GB rate.
How are request charges calculated?
Request count is divided by the selected billing unit and multiplied by its price. Usage is not rounded into whole blocks; verify any minimum or rounding rules on the provider invoice.
How does the free egress allowance work?
The calculator subtracts the allowance from outbound data for the selected period and never lets billable egress fall below zero. Enter zero if the workload or route is not eligible.
Does the calculator support tiered pricing?
Not directly. Use a blended or marginal rate, or model each tier separately and add the totals.
Are my storage and pricing inputs uploaded?
No. Calculations, copied results, and CSV creation run locally in your browser.
Limits and disclaimer
This calculator is a planning aid, not a provider quote, invoice, tax calculation, or financial recommendation. Pricing can vary by region, storage class, operation, destination, tier, commitment, currency conversion, and contract. Minimum storage duration, early deletion, replication, lifecycle transitions, metadata, encryption key operations, support, taxes, and discounts are excluded unless incorporated into your entered rates. Confirm production budgets and migration decisions with current provider documentation, contract terms, billing exports, and representative workload measurements.