Part-Time and Ultra-Short-Hour Workers
Part-time Worker
What is part-time work?
- An employee whose contractual working hours are shorter than those of a full-time employee
- As a rule, working conditions are set in proportion to hours
- Rules on ultra-short-hour work are revised often
Once you start using part-time workers, the basic unit of labor-cost management shifts from “how many people” to “how many hours.” Splitting one full-time position into two hires does not cut total cost exactly in half: weekly holiday pay, annual leave, severance benefits, and the four major social insurances are each calculated separately according to each person’s contractual hours. Because the single contractual-hours figure in the contract determines which rules apply to that person, the hours you write down at hiring are effectively your labor-cost design. If you let on-site store managers set weekly hours on the fly, headquarters ends up settling the consequences all at once, years later.
In practice, the dividing line is whether contractual hours reach 15 per week, averaged over 4 weeks. The Labor Standards Act does not apply weekly holiday pay or annual leave provisions to employees below this threshold, and retirement benefit laws split coverage on the same basis. Other schemes use different criteria, such as 60 hours a month for health insurance and length of continuous service for employment insurance, so one person is often covered by some insurance programs but not others. For part-time employees at 15 hours or more, annual leave is generally the full-time entitlement multiplied by the ratio of their contractual hours, and granted in hours rather than days.
Overtime for part-time workers falls under separate rules. The Act on the Protection of Fixed-Term and Part-Time Workers requires the worker’s consent before you assign work beyond their contractual hours, caps it at 12 hours per week, and requires a premium of at least 50% of the ordinary wage on the excess. A payroll ledger that reasons “they never exceeded 8 hours a day or 40 hours a week, so no premium is due” gets it wrong at exactly this point.
The most common problem is when contract hours and actual hours diverge. If the paperwork says 14 hours a week but staff are made to work 18 to 20 hours whenever it gets busy, a dispute turns on the repeated pattern of actual work, not the paperwork. A workplace that skipped weekly holiday pay and annual leave because it believed it had kept hours under 15 must calculate three years of back pay at once (the limitation period for wage claims). Add retirement benefits, and the amount spirals out of control. Updating the contract every time the schedule changes is the cheapest prevention.
Hwi KimCEO of HRDIST & Talent Development Systems Consultant
Inwoo LeeExpert in Leadership, Communication & Performance ManagementThe Labor Standards Act defines a part-time employee as one whose contractual working hours are shorter than those of a full-time employee, and sets the principle that working conditions be determined in proportion to working hours. The Act on the Protection, etc. of Fixed-Term and Part-Time Employees also prohibits discriminatory treatment.
This is the story of Company A, which runs 14 household goods stores (a hypothetical example). With 38 full-time employees, 92 part-time employees, and annual revenue of KRW 31 (≈ US$1) billion, most store staff were on 14-hour-a-week contracts. When a departing employee filed a complaint over unpaid weekly holiday pay, the company launched a three-month review of every employee.
- When the HR manager pulled attendance records for the past six months, 41 of the 92 employees on 14-hour contracts were averaging more than 16 hours over four weeks.
- Store managers said they had only asked for “an hour or two extra when it got busy,” but the company’s labor attorney was blunt: “if it keeps happening, that becomes the contractual working hours.”
- Company A converted 41 people to 20-hour weekly contracts and standardized the remaining stores at 12 hours a week. When a contract and a work schedule didn’t match, the store manager’s KPI score took a hit.
- They built logic into the payroll system to automatically add a 50% premium on ordinary wages for hours beyond contractual hours, and paid KRW 68 million (≈ US$50,900) in back pay for three years of unpaid weekly holiday pay.
- Six months after the review, the number of employees whose contracts and actual hours didn’t match fell from 41 to 3. There were no further complaints, and quarterly turnover among part-time staff dropped from 34% to 21%.