GBmonth

GBmonth is a unit used in information technology to quantify data storage over time. It combines data volume with duration, defined as one gigabyte stored for one calendar month. It provides a simple way to express the total amount of data stored across a given billing or analysis period. Practically, GB-months can be computed by multiplying the stored data volume (in GB) by the fraction of a month during which the data is stored. For example, storing 100 GB for a 30-day month yields 100 GB-months, while storing 100 GB for 15 days yields about 50 GB-months (100 × 15/30). For a month with 31 days, use 31 as the denominator.

In cloud storage pricing, providers may quote charges per GB-month, sometimes with adjustments for data redundancy or access patterns. GB-months are also used in capacity planning and data-retention analyses to estimate the total storage burden over time.

Limitations include that GB-months do not reflect access frequency, input/output operations, or performance, and conversions between months with different lengths can introduce small variances. Some vendors may use GB-months alongside other metrics such as GB, TB, or IOPS to describe service usage.

See also: gigabyte, month, data storage, cloud storage pricing.