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Hourly Wage & Overtime Pay Calculator | Convert Monthly Salary to Hourly Rate (Japan)

Convert your monthly salary to an hourly rate and estimate overtime pay using Japan's statutory minimum premium rates for overtime, holiday, and late-night work. This tool is based on Japanese labor law and is intended for employees working under Japanese employment rules. Everything is calculated in your browser only — nothing is sent anywhere.

If your salary includes allowances that can legally be excluded from the overtime calculation base (e.g. commuting or family allowance), subtract them before entering the amount.

How to determine average monthly scheduled hours

Overtime hours breakdown (leave blank for 0)

Overtime (within 60 hours/month)

Overtime (beyond 60 hours/month)

Statutory holiday work

Late-night work only (not classified as overtime or holiday work)

All amounts and hours are calculated in your browser only and are never sent anywhere.

Result

Enter your monthly salary and scheduled hours to see the result instantly.

How to use

  1. Enter your monthly salary (base amount) and average monthly scheduled hours, either directly or calculated from your annual holidays and daily scheduled hours.
  2. Enter the hours for overtime, holiday work, and late-night work in each category. If known, also enter the overtime pay you actually received.
  3. The base hourly wage, premium pay for each category, estimated total overtime pay, and estimated shortfall appear instantly.

How it works

Hourly rate formula

Base hourly wage = monthly salary (base amount) ÷ average monthly scheduled hours

Average monthly scheduled hours can be determined in one of two ways:

  • Direct input: use a value you already know.
  • Calculated from annual holidays: average monthly scheduled hours = (365 − annual holidays) × daily scheduled hours ÷ 12

Basis for the premium rates

This tool is based on Japanese labor law. The premium rates for overtime, holiday, and late-night work follow the statutory minimum rates published by Japan's Ministry of Health, Labour and Welfare ("確かめよう労働条件").

  • Overtime (within 60 hours/month): 25% or more
  • Overtime (beyond 60 hours/month): 50% or more
  • Statutory holiday work: 35% or more
  • Late-night work (22:00–5:00): 25% or more (stacks with other premiums)
  • Overtime (within 60h) + late-night: 50% or more
  • Overtime (beyond 60h) + late-night: 75% or more
  • Holiday work + late-night: 60% or more

The 50% premium for overtime beyond 60 hours/month has applied to all companies regardless of size since April 1, 2023, when the grace period for small and medium-sized enterprises was abolished. If your employer's work rules set a higher rate than the statutory minimum, that higher rate applies instead.

About the 60-hour split

This tool asks you to enter "overtime within 60 hours" and "overtime beyond 60 hours" as separate fields. You need to determine from your own timesheet which portion of your late-night hours fall in each bucket — the tool cannot infer this automatically.

How the estimate is calculated

For each category, the "of which late-night" hours are separated from the total, and the corresponding premium rate is applied to each portion using the base hourly wage; the results are summed.

About the estimated shortfall

If you enter the overtime pay you actually received, the tool shows the difference from the estimated total. This is a rough reference for comparing against your pay slip, not evidence you can submit directly to a labor standards office or in litigation. Details such as excludable allowances or a fixed ("deemed") overtime allowance are not accounted for. For an accurate calculation or legal action, consult a certified social insurance labor consultant (社会保険労務士) or lawyer.

FAQ

Is my salary or hours data sent anywhere?

No. All calculations happen entirely in your browser; nothing is sent to any server.

Where do the premium rates come from?

They are the statutory minimum rates under Japan's Labor Standards Act, as published by the Ministry of Health, Labour and Welfare: 25% for overtime (50% beyond 60 hours/month), 35% for statutory holiday work, and 25% for late-night work (which stacks with the other premiums). If your employer's work rules specify a higher rate, that higher rate is correct instead.

Does the 50% premium for overtime beyond 60 hours apply to every company?

Yes. Small and medium-sized enterprises previously had a grace period, but it was abolished on April 1, 2023, and the rule now applies to all companies regardless of size.

Should I include commuting or family allowance in the monthly salary field?

No, we recommend excluding them. Japanese labor law allows certain allowances (commuting, family, housing, etc., a limited list) to be excluded from the overtime calculation base. If you receive such allowances, subtract them before entering the amount in the "monthly salary" field.

Can I submit the estimated shortfall directly to a labor standards office?

No. This is only a rough estimate and does not account for factors such as excludable allowances or a fixed ("deemed") overtime allowance in your contract. For an accurate calculation or an actual claim, consult a certified social insurance labor consultant or a lawyer.

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