When running the reservation revenue report in **Accrual** mode, there are two different calculations going on behind the scenes to create the values in the accrual columns, depending on the **Scheduled Dates **of the reservation. These two modes are **Monthly Math** and **Nightly Math**.

__Monthly Math__

Monthly math works for all reservations that span full months (e.g. 9/1/20-8/31/21 or 9/1/20-9/1/21). In this case, the accrual amount for each month is Reservation Total / (Months in Reservation). For the accrual columns to use the **Monthly Math** calculation, the **Scheduled Arrival Date** must be the first of a month, and the **Scheduled Departure Date** must be either the last day of a month or the first of a month.

**Monthly Math Example:**

**Scheduled Dates****:** 1/1/20-12/31/20

**Reservation Total:** $2400 flat rate

**Nights in Reservation:** 365

**Months in Reservation:** 12

**Logic:** Monthly Math

**Calculation: **2400/12 = $200/month

*Accrual Columns show $200/month for all months of 2020*

__Nightly Math__

Nightly math works for all reservations that include a partial month (e.g. 9/15/20-8/31/21). For this case the accrual amount for each month is (Reservation Total / Number of Reservation Nights) * Nights in Month. The **Nightly Math** logic is in effect whenever the requirements for monthly math are not met.

**Nightly Math Example:**

**Scheduled Dates****:** 1/15/20-12/31/20

**Reservation Total:** $2400 flat rate

**Nights in Reservation:** 351

**Months in Reservation:** 12

**Logic:** Nightly Math

**Calculation: **2400/351 * nights in relevant month

** Accrual Columns depend on nights in month, eg: **Jan (2400/351)*17 nights = $116.24; Feb (2400/351)*29 nights = $198.29; Mar (2400/351)*31 nights = $211.97; etc.

__Credit Notes__

Credit notes linked to a reservation invoice apply in the accrual columns equally from the date of credit note issuance to the end of the reservation. Credit notes issued after the reservation departure date do not affect the accrual columns.

**Credit Note Example:**

**Scheduled Dates****:** 1/1/20-12/31/20

**Reservation Total:** $2400 flat rate

**Credit Note amount:** $600

**Credit Note date:** 7/12/20

**Months in Reservation:** 12

**Logic:** Monthly Math

**Calculation: **2400/12 = $200/month

*Accrual Columns show $200/month for Jan-Jun of 2020, and $100/month for Jul-Dec 2020.*