How do I calculate monthly working hours?

Monthly working hours are calculated by multiplying weekly hours by 4.33, which is the average number of weeks per month (52 weeks ÷ 12 months). For example, 40 h/week × 4.33 = 173 h/month.

What is the part-time salary percentage?

The salary percentage is calculated by dividing actual weekly hours by full-time weekly hours. If the full-time salary is €3,000 and you work 32h/40h = 80% of full time, your part-time salary is €2,400/month.

How many hours per week is full-time in Finland?

In Finland, the standard full-time working week is 40 hours. However, many sectors follow 37.5 or 38.75 hours per week based on collective agreements. Always check your own employment contract or collective agreement.

How does part-time work affect annual salary?

Annual salary is calculated by multiplying monthly salary by 12. In part-time work, the annual salary decreases proportionally: for example, 80% employment means 80% of the full-time annual salary.

Work Hours Calculator

Calculate your weekly, monthly and annual working hours. Switch to the salary calculator to find out how much you earn working part-time compared to full-time.

Hours per day: 8 h

0,5 h8 h16 h

Days per week: 5 d

157

Hours / week	40 h
Hours / month	173,2 h
Hours / year	2 080 h
Share of full-time(full-time = 40 h/week)	100 %

0 %100 %100 %

Hours calculator: monthly hours = weekly hours × 4.33. Salary calculator: salary scales linearly with working hours.

This work hours calculator helps you understand your working time on a weekly, monthly and yearly basis, and to work out part-time pay relative to full-time. It suits both employees and managers who want a quick picture of hours worked and the part-time ratio.

How the calculator works and what it’s for▾

How the work hours calculator works

The calculator derives your total working hours from your weekly working time. Once you know your weekly hours, the monthly and annual totals follow by multiplying weekly hours by the number of working weeks in that period.

The part-time share is found by dividing part-time hours by full-time hours. That percentage can then be applied to a full-time salary to estimate the pay matching part-time hours.

What you enter and what you get

Typically you provide your weekly working time, and where needed a full-time reference and a salary. The results show your hours over different periods and the part-time percentage.

The output makes clear how much working time builds up over the longer term and how a part-time role compares with full-time work in terms of both hours and pay.

Who it is for

The calculator is useful for part-time workers who want to check their pay is correct, and for job seekers comparing the hours and salaries of different roles.

Managers and entrepreneurs can also use it for shift planning and for a rough estimate of labour costs before running detailed payroll.

Good to know

The calculator gives an indicative picture and does not replace official payroll or the working time set by a collective agreement. Holidays, public holidays and overtime can change actual hours.

Always check your contract and any applicable collective agreement, as definitions of working time and ways of calculating monthly hours can vary between sectors.

🔄 Reviewed June 2026