How to Calculate Overtime Pay: Hourly Rate, Premium Rates, and Fixed Overtime
Overtime pay is calculated as "hourly rate × premium rate × overtime hours." This article explains, in plain terms, how to correctly find the hourly rate, the premium rates of 25% for overtime, 25% for late-night, and 35% for holiday work, how fixed (deemed) overtime works, the premium for hours over 60 a month, and concrete worked examples.
Have you ever looked at a pay slip and wondered, "Is this overtime amount calculated correctly?" Overtime pay is not decided by feel; it follows clear rules based on labor law. Once you grasp the basic idea, you can check for yourself whether your overtime pay is roughly right. This article explains how to calculate overtime pay in plain terms, in the order of finding the hourly rate, the premium rates, and fixed overtime, with concrete examples.
The Basics: Three Factors
Boiled down, calculating overtime pay is a multiplication of the following three factors.
Overtime pay = hourly rate × premium rate × overtime hours
In other words, if you know "how much you earn per hour" (the hourly rate), "how much it is marked up" (the premium rate), and "how many hours you worked overtime," you can calculate your overtime pay. Conversely, if you misjudge any one of these three, the amount will be off. The easiest one to get wrong is how the hourly rate is derived.
To grasp the big picture by plugging in your own numbers, try entering your monthly salary and overtime hours into the Overtime Pay Calculator to check the approximate amount.
How to Find the Hourly Rate (Base Wage)
The starting point for overtime calculation is the hourly rate. You find it as "base wage divided by the average scheduled working hours per month."
Hourly rate = monthly base wage ÷ average scheduled working hours per month
The base wage is the portion of your monthly salary used as the basis for overtime calculation. Note that not all of your monthly salary counts. By law, allowances such as the following may be excluded from the base wage.
- Family / dependent allowances
- Commuting allowance
- Separation allowance and child education allowance
- Housing allowance (when it meets certain conditions)
- Wages paid on an irregular basis, and bonuses (paid for periods exceeding one month)
The amount left after subtracting these from your monthly salary is a guide to the base wage. Next, find the average scheduled working hours per month. This is "(365 days − annual holidays) × scheduled hours per day ÷ 12 months." For example, with 120 annual holidays and an 8-hour day, it is (365 − 120) × 8 ÷ 12 ≈ 163 hours.
If the base wage is 260,000 yen per month and the average scheduled hours are 163, the hourly rate is 260,000 ÷ 163 ≈ 1,595 yen. This hourly rate is the foundation for all the premium calculations that follow. When you want to quickly know your hourly rate from your salary and annual holidays, converting it to an hourly basis with the Salary Converter makes it easier to get a feel for it.
Premium Rates: 25% Overtime, 25% Late-Night, 35% Holiday
Overtime pay is higher than ordinary work because a premium rate is added on top. Labor law sets minimum premium rates depending on the situation.
| Type | Condition | Premium rate |
|---|---|---|
| Overtime work | Work beyond 8 hours a day / 40 hours a week | 25% or more |
| Late-night work | Work between 22:00 and 5:00 | 25% or more |
| Holiday work | Work on a statutory holiday | 35% or more |
| Overtime + late-night | Overtime extending into late-night hours | 50% or more |
| Holiday + late-night | Holiday work extending into late-night hours | 60% or more |
The key point is that these premiums stack and add together. For example, if overtime past your scheduled end time extends into late-night hours (after 22:00), the 25% for overtime plus the 25% for late-night make a combined premium of 50% or more. Working on a holiday into the late-night hours is 35% + 25% = 60% or more.
Note that "holiday" here refers to the statutory legal holiday (one day a week, or four days in four weeks). If you work on a company-defined scheduled day off (for example, the second day of a two-day weekend), it is generally treated not as a holiday premium but as an overtime premium (25%). You can confirm which day is your legal holiday in your company's work rules.
Premium for Overtime Beyond 60 Hours a Month
For the portion of monthly overtime that exceeds 60 hours, the premium rate is raised to 50% or more. There used to be a grace measure for small and medium-sized companies, but it now applies to all companies. In a month with sustained long overtime, whether this over-60-hours premium is correctly reflected is another point worth checking.
What Is Fixed (Deemed) Overtime
Fixed overtime pay (deemed overtime) is a system that pays a set number of overtime hours each month, included in your salary in advance, regardless of the actual overtime worked. It is set up as something like "fixed overtime of 30,000 yen (for 20 hours a month)." You often see this in job listings and employment contracts.
Having fixed overtime is not illegal in itself, but it is important to understand the following points.
- It must be clear how many hours it covers. If it only says "overtime is included in the base salary" and the hours or amount cannot be distinguished, it may not be recognized as valid.
- Overtime beyond the deemed hours must be paid separately. For example, with fixed overtime for 20 hours a month, if you actually work 30 hours, the excess 10 hours should in principle be paid additionally.
- Fixed overtime is generally not reduced even if you do not reach the deemed hours.
In short, fixed overtime does not mean "unlimited overtime." It is important to know how many hours your fixed overtime corresponds to and compare it with your actual overtime. To estimate whether there is any excess, calculate the amount based on your actual overtime hours with the Overtime Pay Calculator and compare it with the fixed portion.
Worked Examples
Let's confirm the above with concrete numbers. We assume the following.
- Base wage: 260,000 yen per month
- Average scheduled working hours per month: 163 hours
- Hourly rate: 260,000 ÷ 163 ≈ 1,595 yen
If you are unsure whether this hourly rate is right, convert your monthly salary to an hourly figure with the Salary Converter and compare the results.
Example 1: 20 hours of ordinary overtime
Hourly rate 1,595 yen × premium 1.25 × 20 hours = about 39,875 yen. This is the overtime pay for 20 hours of ordinary overtime past the scheduled end time.
Example 2: When 5 of those hours fall in the late-night period (after 22:00)
The 5 late-night hours have a premium of 1.5 (25% overtime + 25% late-night).
- Ordinary overtime 15 hours: 1,595 × 1.25 × 15 ≈ 29,906 yen
- Late-night 5 hours: 1,595 × 1.5 × 5 ≈ 11,963 yen
Total about 41,869 yen. The late-night portion is added on, making it higher than Example 1.
Example 3: Working 8 hours on a statutory holiday
The premium rate for holiday work is 35%, so 1,595 × 1.35 × 8 = about 17,226 yen. This is calculated separately from ordinary overtime.
As you can see, even for the same number of overtime hours, the amount changes depending on "when and under which category you worked." When multiple categories are mixed, doing it by hand gets tedious, so entering the hours into the Overtime Pay Calculator and letting it calculate each category automatically makes checking much easier.
Cautions: How to Check Your Own Case
The calculations introduced in this article are only a guide based on general rules. Actual overtime pay differs in detail depending on your company's system and employment type. Keep the following in mind.
- The range of allowances included in the base wage can be handled differently depending on the company's wage rules.
- The setting of scheduled working hours and legal holidays is specified in the work rules. Start by checking your own company's work rules.
- If a variable working hours system, flextime system, or discretionary work system is in place, overtime is counted differently from the norm.
- If you qualify as a manager or supervisor, overtime and holiday premiums do not apply, while the late-night premium still does.
If you feel "the numbers don't add up" or "there may be unpaid wages," the first step is to gather records such as your pay slips, work rules, and time cards, and check with your workplace's HR or labor affairs staff. If that does not resolve it, you can also consult a Labor Standards Inspection Office, or a professional such as a labor and social security attorney or a lawyer.
Overtime pay rests on the simple formula "hourly rate × premium rate × overtime hours." First, enter your own numbers into the Overtime Pay Calculator to grasp the big picture, then compare it against the amount on your pay slip. Understanding the mechanism is the first step toward receiving pay that matches your work.
Please note that this article is intended to provide general information and does not present a conclusion for any individual case. Make your decision after checking the latest official information (such as Ministry of Health, Labour and Welfare materials and laws) and your own company's work rules, and consult a professional where needed.
FAQ
How do I calculate overtime pay?
Overtime pay is calculated as "hourly rate × premium rate × overtime hours." Find the hourly rate as "base wage ÷ average scheduled working hours per month." The minimum premium rates are 25% or more for ordinary overtime, 25% or more for late-night work, and 35% or more for statutory holiday work. These premiums stack and add together.
What are the premium rates for overtime, late-night, and holiday work?
The legal minimums are 25% or more for overtime, 25% or more for late-night work (22:00 to 5:00), and 35% or more for statutory holiday work. If overtime extends into late-night hours, it is 25% + 25% = 50% or more; if holiday work extends into late-night hours, it is 35% + 25% = 60% or more. In addition, overtime exceeding 60 hours a month is raised to 50% or more.
With fixed (deemed) overtime, is no extra paid no matter how much I work?
No. Fixed overtime is overtime pay for "a set number of hours paid in advance." For example, with fixed overtime for 20 hours a month, if you actually work 30 hours, the excess 10 hours should in principle be paid separately. Also, for fixed overtime to be valid, it must be clear how many hours and how much it covers.
Does the base wage include all of my monthly salary?
No. Allowances such as family, commuting, separation, and child education allowances, housing allowance meeting certain conditions, and wages paid for periods exceeding one month such as bonuses may be excluded from the base wage. The amount left after subtracting these from your monthly salary is the basis for calculating the hourly rate. The specific treatment can vary by the company's wage rules.
Are the amounts I enter into the Overtime Pay Calculator sent to a server?
WAZA TOOLS' Overtime Pay Calculator runs entirely in your browser, so the monthly salary and overtime hours you enter are never sent to or stored on a server. It works on smartphones too, and you can estimate your overtime pay as many times as you like, for free.