The United States does not have a federally mandated annual leave policy for private sector employees. Instead, companies are free to set their own policies and offer vacation time, sick days, and other forms of paid time off as they see fit. The average number of PTO days for full-time employees in the United States was 17.1 days per year.

Iran is the most generous country when it comes to paid time off, with 27 holidays and 26 days of paid leave contributing to a total of 53 paid vacation days.

Vacation and PTO (Paid Time Off) are both types of paid leave, but they differ in how they are earned and used. Vacation time is typically earned over time and can only be used for planned time off, while PTO combines vacation, sick leave, and other types of paid leave into a single bank of time that can be used for any purpose.

Vacation and annual leave are both types of paid time off, but the main difference is that vacation is typically used for leisure and personal activities, while the annual leave is more flexible and can be used for any purpose, including personal and medical needs.

The most common PTO (paid time off) policy in the US is the accrual method, where employees earn a certain amount of PTO hours for each hour worked, typically ranging from 0.5 to 1.5 hours per week depending on the company's policy. Once accrued, employees can use their PTO hours for vacation, sick leave, or personal time off, subject to their employer's approval.