Calculate the effective cost of each stored gigabyte-month by combining service charges that appear separately on a cloud bill. The result makes pricing tiers and vendors easier to compare while preserving the actual workload volume behind the unit rate.
Unit cost = (Primary cost + secondary charges) ÷ workload volume
Terabytes are converted to 1,000 gigabytes for the displayed GB-month rate.
The main result normalizes the total bill by workload volume. It is useful for trend and vendor comparisons only when the included charge categories and workload definitions stay consistent.
Cloud invoices may use decimal or binary storage units and may price read, write, retrieval, and transfer separately. Match this model to the units on your invoice.
A $1,800 capacity charge plus $450 of request and transfer fees across 250 TB-month costs $0.009 per GB-month.
Use a period that matches your invoice and a workload window representative of normal operations. Avoid mixing daily usage with monthly charges.
Yes. The formulas are provider-neutral, but you should enter costs, discounts, and units from the provider’s own bill or quote.
Enter net costs after recurring credits when comparing actual bills. Model temporary promotional credits separately so they do not distort a long-term estimate.
Invoices can include tiered rates, regional pricing, taxes, free allowances, minimum charges, and timing adjustments that this planning model does not reproduce.
Use average data for unit economics and routine utilization. Use peak data and an explicit safety buffer when the decision concerns capacity or resilience.
| Input type | How to use it |
|---|---|
| Cost or capacity | Use values from the same scope and period. |
| Percentage | Enter the displayed percent, such as 20 for 20%. |
| Planning horizon | Use whole months and revisit assumptions regularly. |