Rent per calendar month is calculated by taking a provided value for rent per week and first converting to rent per year. Then, the rent per year is converted into rent per month.

Landlords usually accept rent payments from tenants once per month. However, in some cases, apartment rents are advertised in blocks of time other than full months, necessitating a few mathematical conversions. When rent is advertised as a weekly price, multiplying by 52 gives a yearly price. Dividing the yearly price by 12 gives the monthly price. Given a rent of $200 per week as an example, $200 times 52 and then divided by 12 gives a monthly rent of $866.67.