# POD Usage Charges and Billing

Back to documentation indexThe POD billing cycle begins at midnight on the 26th of each month and ends at 11:59 on the 25th of the following month with all times expressed in GMT. Invoicing takes place within 5 business days of the end of the billing cycle.

### Core Hours

Core hours are computed by summing the core hour usage of each successfully run job that completes within the billing period, regardless of when it started. The core hours for a particular job are computed by multiplying the walltime by the number of cores. Walltime is expressed in seconds so dividing by seconds/hr gives us the following formula:

core hours = (walltime x number of cores) / 3600.0

### Server Instance Hours

For non-free server instances, usage charges occur for the periods where the instance is up and available. The server uptime, expressed in seconds, is used in the calculation.

### Storage

POD storage is based on allocated storage; your monthly bill will reflect the allocated storage amount not the amount of storage you are actually using. To compute your monthly bill, we compute the sum of the daily charges; one number for each day in the billing cycle. To compute the charge for a given day, we take the maximum allocated storage on that calendar day and multiply by a*daily factor*, representing an average number of days per billing cycle (365 / 12.0).

For example, the monthly bill for a storage volume of 10GB where the billing cycle consisted of 30 days would be computed as follows:

daily storage amount: 10 * 1/DAYS_PER_CYCLE = 0.328767123 multiplied by the number of days in the billing cycle: 0.328767123 * 30 = 9.86301369 now, to prepare the bill, multiply by the GB/mon rate of 0.10: 9.86301369 * $0.10 = 0.986301369 which would be finally rounded to: $0.99

### Usage and Reports

Usage amounts and charges are available in the "Usage and Reports" page. These numbers are generally subject to a delay (particularly for core hours). One thing to note is that the billing estimates displayed in the portal do not reflect any potential account credits. This could include rollover credits or credits applied due to failed jobs. Credits will be reflected on the monthly invoice.