A salary expressed per hour, month or year can only be compared correctly when the same working-time basis is used.
The Bethemesh salary calculator automatically converts hourly, weekly, monthly and annual compensation.
Salary conversion formulas
Annual salary = Hourly rate × Hours per week × Weeks per year
Monthly salary = Annual salary / 12
Hourly rate = Annual salary / (Hours per week × Weeks per year)
At €20/hour, 35 hours per week and 52 weeks, the annual equivalent is €36,400 and the monthly average is about €3,033.33.
Why 151.67 hours per month at 35 hours per week?
35 × 52 = 1,820 hours/year
1,820 / 12 ≈ 151.67 hours/month
This is an average monthly time basis, not a statement that every calendar month contains the same working hours.