The calculator takes different lifestyles into account.
A new calculator has been launched to tell you how often you should wash your bed sheets.
Secret Linen Store has introduced the service, and says you don't have to clean your bed linen every week.
The calculator takes into account whether you share your bed with pets, how many times you shower, and whether you eat in bed.
People who shower often, don't have pets, and sleep in pyjamas can leave it a month without washing their sheets.
Those who snack in bed, sleep naked, share their beds with a dog and sweat a lot should do a weekly wash of their bed linen.