What Is Double Work? Complete Guide to Pros, Cons & How to Get Started

"I want to increase my income, but what's double work really like?" "What's the difference between side jobs and double work?" Many people have these questions.

In recent years, interest in double work has surged against the backdrop of work-style reform and rising prices. Japan's Ministry of Health, Labour and Welfare has revised its guidelines for promoting side jobs and dual employment, and corporate acceptance continues to grow.

This article comprehensively covers everything from the basic definition of double work, its pros and cons, tax filing and social insurance considerations, to step-by-step instructions for getting started. Whether you're about to start or already considering it, read on to the end.

What Is Double Work? A Clear Explanation of the Basics

Double work (daburu wāku) refers to simultaneously holding two or more jobs. It's a Japanese-English compound of "double" and "work" unique to Japan.

Typical examples include working as a company employee on weekdays while taking a part-time job on weekends, or holding two part-time positions simultaneously. There are no restrictions on employment type—any combination of full-time, dispatch, part-time, or casual work qualifies as double work.

Differences Between Double Work, Side Jobs, and Dual Employment

Double work, side jobs (fukugyō), and dual employment (kengyō) are similar concepts with subtle differences.

A "side job" refers to supplementary work secondary to a clearly defined main job. "Dual employment" means operating multiple businesses or jobs at a main-job level, like a farmer taking other work during winter. "Double work" broadly encompasses holding two or more jobs simultaneously without distinguishing between primary and secondary roles.

In other words, side jobs and dual employment can be considered forms of double work. Since there's no legal definition, it's generally understood as a work style involving multiple simultaneous jobs.

Why Double Work Is Getting Attention

Several social factors explain the growing attention on double work.

First, rising prices and stagnant real wages. As daily living costs increase while salary growth fails to keep pace, the need for multiple income sources has intensified.

Second, government promotion of side work and dual employment. In 2018, the Ministry of Health, Labour and Welfare removed side job prohibition clauses from its model employment rules, and in 2022, revised guidelines encouraged companies to allow side work. The number of companies permitting side jobs has been increasing year after year.

Furthermore, the spread of remote work has eliminated commuting time and enabled flexible scheduling. With more jobs that can be done from home, the barrier to double work has dropped significantly.

5 Benefits of Double Work

1. Increase Your Income

The biggest benefit of double work is adding income sources. Beyond supplementing what your main job can't cover, it creates room for savings and investments. Even tens of thousands of yen in monthly side income adds up to hundreds of thousands annually, significantly improving your quality of life.

2. Expand Your Skills and Experience

Working in different industries or roles lets you gain skills and experience unavailable through your main job alone. For example, a sales professional doing web writing on the side improves their writing skills, or an engineer doing weekend design work picks up UI/UX knowledge—often benefiting the main job as well.

3. Hedges Financial Risk

Not depending on a single income source serves as a financial risk hedge. If your main employer goes bankrupt or you face layoffs, having another job reduces the risk of complete financial hardship. In uncertain economic times, income diversification provides significant peace of mind.

4. Expand Your Network

Working at multiple workplaces creates connections you'd never make through your main job alone. Cross-industry networks not only expand career possibilities but can also lead to unexpected business opportunities or job offers.

5. Explore Career Paths That Suit You

For those who haven't found their ideal career, double work is an excellent low-risk opportunity to try new fields. Since you can experience different work without leaving your main job, it's also highly effective as a pre-career-change trial.

5 Drawbacks of Double Work

1. Significant Physical and Mental Burden

The biggest drawback of double work is the toll on mind and body. Working on days off or in the evenings means less rest and accumulated fatigue. Chronic exhaustion can lead to health issues and mental health deterioration, making self-management crucial.

2. Risk of Declining Main Job Performance

Accumulated fatigue and stress can affect your main job. Lateness, dozing off, or decreased concentration can impact evaluations from supervisors and colleagues. Since double work only works when your main job is solid, keeping priorities straight is essential.

3. Less Personal Time

Juggling two jobs inevitably reduces free time. Time with family, friends, and hobbies is likely to be sacrificed, requiring careful consideration from a work-life balance perspective. If you have a partner or family, discuss this thoroughly beforehand.

4. Increased Administrative Burden Like Tax Filing

If your annual side income exceeds 200,000 yen, tax filing is required. Additionally, resident tax calculations and social insurance procedures may require complex handling. There's also risk of missed filings or additional tax assessments due to lack of knowledge, so learning basic tax fundamentals is important.

5. Potential Violation of Employment Rules

Some companies prohibit side work and dual employment in their rules. Starting double work secretly and being discovered could result in disciplinary action. Always check your employment rules before starting and submit any required notifications to your company.

What to Check Before Starting Double Work

Check Employment Rules

The most important step is reviewing your main employer's employment rules. Whether side work is completely banned, requires notification, or is conditionally permitted varies by company. If unsure, directly consult your HR department.

Assess Impact on Your Main Job

Objectively evaluate whether the double work content and schedule could negatively impact your main job performance. Working for competitors or handling confidential information can cause problems even if technically permitted by employment rules.

Plan for Health Management

Sustaining double work requires health management. Set personal rules like securing at least one complete day off per week and maintaining 6+ hours of sleep. There's no point if your health breaks down.

Tax Filing and Tax Considerations for Double Work

When Tax Filing Is Required

For company employees doing double work, tax filing is required when side job income (revenue minus expenses) exceeds 200,000 yen annually. Note that this applies to income tax; resident tax filing is required regardless of the amount.

Can Your Company Discover Your Double Work Through Resident Tax?

The most common way employers discover double work is through increased resident tax. When side income is added, resident tax rises, and your company's payroll department may notice. To avoid this, select "ordinary collection" (self-payment) for resident tax during tax filing. However, municipality policies vary, so check in advance.

Social Insurance Handling

If you meet social insurance enrollment requirements at two or more workplaces, you must file a "Multiple Workplace Employment Notification." This applies when you work 20+ hours per week at each employer and earn 88,000 yen or more monthly. Failure to file can result in penalties later, so complete the procedure promptly if applicable.

10 Recommended Jobs for Double Work

Jobs well-suited for double work offer schedule flexibility and compatibility with your main job. Here are some representative options.

Remote/Work-from-Home

Web writing is beginner-friendly and leverages writing skills. Data entry focuses on simple tasks ideal for spare moments. Online assistants remotely support corporate back-office operations and are popular among those with administrative experience. Programming and web development command higher rates and are particularly recommended for those with IT skills.

In-Person/On-Site

Restaurant work offers late-night and weekend shifts, making it a double work classic. Convenience store or supermarket cashier work allows short shifts during early morning or late-night hours. Event staffing lets you participate on a one-off basis, fitting around your own schedule.

Skill-Based

Tutoring leverages specialized knowledge with relatively high hourly rates. Translation and interpreting utilize language skills with many work-from-home opportunities. Consulting and advisory work involves providing professional advice based on specialized experience and knowledge, with high compensation potential.

5 Steps to Start Double Work

Step 1: Clarify Your Purpose and Goals

Start by clarifying why you want to do double work. How much do you want to earn monthly? Is skill development the goal? Are you considering eventual independence? A clear purpose leads to better job selection and sustained motivation.

Step 2: Review Your Employer's Rules

As mentioned, checking employment rules is essential. Secretly starting double work at a company that prohibits it carries high risk, so first understand the rules and complete any required procedures.

Step 3: Map Out Your Available Time

Review your weekly schedule and specifically list the time available for double work. Setting realistic boundaries like 2 hours on weekday evenings and 4 hours on weekends is the key to sustainability.

Step 4: Find Work That Suits You

Choose work based on your available time slots, existing skills, and areas of interest. Using job sites and crowdsourcing services makes finding suitable opportunities easier. Start small and gradually increase your workload as you adjust.

Step 5: Understand Tax and Insurance Procedures

Once you start double work, don't forget to handle tax filing requirements, resident tax payment methods, and social insurance procedures. If unsure, consult a tax accountant or check the National Tax Agency's website.

Tips for Sustaining Double Work Long-Term

Several key points help maintain double work sustainably.

First and foremost, don't overdo it. If you notice any changes in your health or mental state, don't hesitate to rest or reduce your workload. The benefits of double work come from long-term sustainability.

Second, review your finances regularly. Check monthly whether your effective hourly rate makes sense and how you're tracking against your goals. If a job isn't worth the effort, switch to something better early.

Third, clearly separate time for your main job and double work. Without clean boundaries, both can suffer. Setting rules like "side work only from 8-10 PM on weekdays" helps maintain a balanced lifestyle.

Frequently Asked Questions

Q. Is Double Work Illegal?

Double work itself is not illegal. However, doing it secretly when prohibited by your employment rules can result in disciplinary action. Public servants face legal restrictions on side work, so they need to be particularly careful.

Q. Is Tax Filing Unnecessary If Double Work Income Is Under 200,000 Yen?

If your side income is under 200,000 yen annually, income tax filing is generally not required. However, resident tax filing is still necessary. Other situations that require tax filing include medical expense deductions or not using the one-stop exception for hometown tax donations, so judge based on your individual circumstances.

Q. Will My Company Find Out About My Double Work?

Your company may discover it through resident tax notifications. Selecting ordinary collection for resident tax during filing can often prevent company-routed notifications, though policies vary by municipality. If concerned, reporting to your company from the start is the safest approach.

Q. What Are Recommended Job Sites for Double Work?

For remote work, crowdsourcing services like CrowdWorks and Lancers are recommended. For part-time positions, Town Work and Baitoru offer extensive listings. For one-off or spot work, gig apps like Sharefull and Timee are also useful.

Conclusion: Start Double Work with a Plan

Double work offers many benefits including increased income, skill development, and financial risk hedging. However, there are also drawbacks to understand in advance, such as physical demands, impact on your main job, and complex tax procedures.

What matters most is creating a manageable plan while prioritizing your health and main job. After reviewing employment rules, managing your schedule, and learning about taxes, start small and build from there.

We offer trial career change opportunities that let you experience a workplace's atmosphere and job duties before officially joining. If you want to try a new industry as part of your double work, or if you're considering a career change, try using our trial career change service.