Doctors' Enterprise Tax: Insured Treatment Is Exempt

The short answer: enterprise tax only reaches the part insurance does not cover

What falls outside enterprise tax is income from social insurance treatment (社会保険診療)[Local Tax Act, Art. 72-49-12]. The trap is that the line does not match the one drawn for consumption tax. Treatment under workers' compensation and compulsory automobile liability insurance is taxable for enterprise tax yet exempt for consumption tax.

Sources: Local Tax Act, Art. 72-23(3)[Local Tax Act], Wakayama Prefecture tax office[Wakayama Prefecture], National Tax Agency No.6201[NTA].

Medical practice is category 3 business at 5%, and 3% is easy to pick by mistake

Medical practice, dental practice and pharmacy are category 3 businesses, taxed at 5%[Local Tax Act, Art. 72-49-17]. The 3% rate belongs only to massage, shiatsu, acupuncture, moxibustion, judo therapy and farriery. The same category 3 carries two rates, which is where the misreading starts.

Sources: Local Tax Act, Art. 72-2(10) and others[Local Tax Act], Tokyo Metropolitan Bureau of Taxation[Tokyo Bureau of Taxation].

The ¥650,000 blue return special deduction you took for income tax cannot be taken for enterprise tax. The prefecture adds it back to your business income before calculating[Tokyo Bureau of Taxation]. For the whole picture, see the basics of individual enterprise tax.

Medical corporations follow the same shape. Income from social insurance treatment is not included in gross revenue, and its expenses are not included in deductible costs[Local Tax Act, Art. 72-23(2)]. This applies only to medical corporations and certain federations of agricultural cooperatives.

Exemption means "treating both the income and the expenses as if they never happened"

The statute does not say "subtract the exempt income". It says the income and the expenses of social insurance treatment are not included at all[Local Tax Act, Art. 72-49-12]. That is why the way you allocate expenses moves the tax.

There are two ways to allocate. If your books separate the two streams, use those figures; if not, apportion by income[Wakayama Prefecture].

The formula splits by prefecture. Tottori Prefecture's simplified version leaves miscellaneous income out of the numerator[Tottori Prefecture]. We could not confirm Tokyo's form for individuals. Follow the worksheet issued by the prefectural tax office that covers you.

The estimated-expense rule opens at ¥50 million and ¥70 million

For social insurance treatment you may calculate expenses at fixed rates instead of by actual amounts[Act on Special Measures Concerning Taxation, Art. 26]. There are two gates. Social insurance treatment of ¥50 million or less, and total income from medical and dental practice of ¥70 million or less.

• Open to individuals running a medical or dental practice. Pharmacy and the like are excluded
• Unavailable unless the return states that the special rule was applied
• No blue return requirement; a white return works too
• No expiry date. The fiscal 2026 tax reform outline carries no amendment[Ministry of Finance]

The rates in the statute are stacked in layers: 72% up to ¥25 million, 70% up to ¥30 million, 62% up to ¥40 million, 57% up to ¥50 million. The "+¥500,000" figures you see in practice come from flattening those layers into a single line. The statute itself has no fixed add-on.

The quick table and the effective rates are this site's conversion of the statute[Act on Special Measures, Art. 26].

The test is one line. If your actual expense rate on the insurance side is below the effective rate, the estimated-expense rule wins. In the years just after opening, when depreciation is heavy, actual amounts win. Redo the test every year.

Worked example: income tax income falls by ¥3.7 million, enterprise tax does not move at all

The extra expenses created by the estimated-expense rule land on the social insurance side, the side enterprise tax treats as if it did not exist. Income tax falls; enterprise tax stays put.

This site's calculation, applying Wakayama Prefecture's method[Wakayama Prefecture] and Article 26[Act on Special Measures].

At a combined income tax and residence tax rate of 43%, shaving ¥3.7 million is worth about ¥1.59 million. Even so, enterprise tax stays at ¥55,000. The only expenses you can move are the ones on the self-pay side.

What decides it is whether you can tie the cosmetic laser or the orthodontic materials to self-pay treatment. Separate bookkeeping is not always the cheaper route. Compare with your own clinic's figures before deciding.

Workers' compensation and auto liability become exempt sales for consumption tax

Appended Table 2 of the Consumption Tax Act lists treatment under workers' compensation, compulsory automobile liability insurance and pollution compensation as exempt. Midwifery is exempt too[Consumption Tax Act, Appended Table 2]. Those same four sit on the taxable side for enterprise tax. Consumption tax runs the other way.

Counting all of your self-pay income as taxable sales when you test the ¥10 million threshold gives the wrong answer. The test is taxable sales in the base period[NTA No.6501].

Cosmetic surgery, private room charges and over-the-counter medicines are not exempt[NTA No.6201]. Once you become a taxable business, pick the lighter of the two under the simplified and standard methods.

Invoice registration is not urgent if your patients are individuals. Consider it if you take work from businesses, such as occupational physician fees, corporate health checkups or clinical trials. Registering creates a filing obligation even below ¥10 million[NTA No.6501]. For the paperwork in a year of capital spending, see the notification to elect taxable status.

Hospital-employed doctors: moonlighting is Column B, occupational physician fees are salary

Almost every employed doctor who has to file does so because of night duty or outpatient shifts taken on the side. The dependent deduction declaration can only go to one employer. A second job withholds under Column B, with no year-end adjustment.

• File if secondary salary plus non-salary income exceeds ¥200,000
• File unconditionally if salary income exceeds ¥20 million
• Lecture and writing fees are miscellaneous income unless they are a business (10.21% withheld)

The surprise is the occupational physician fee. The National Tax Agency treats a fee received from a business as an occupational physician as salary in principle for income tax purposes[NTA, Q&A]. Even a doctor in private practice receives it as salary income, and it is outside the scope of consumption tax. Note that the Q&A itself concerns consumption tax; the income tax treatment appears in its closing note.

The route for deducting an employed doctor's expenses from salary is the employment expense deduction (特定支出控除). Only the part above half of the salary income deduction can be taken[NTA No.1415]. Conference fees can count as training costs, but your employer has to certify them. For more, see why the employment expense deduction is so hard to use.

What you can do now

1. Look at page two of your return. Check that the income from social insurance treatment is entered in the "exempt income" box.
2. Collect the self-pay expenses. Pull out the spending that belongs only to self-pay treatment, such as cosmetic equipment and orthodontic materials, and compare it with apportioning.
3. Test the estimated-expense rule every year. Compare the effective rate with your actual expense rate, and state it on the return in the years you use it.
4. Check the form with your own office. Whether miscellaneous income goes into the apportionment ratio differs by prefecture.

Start with this year's accounts and total your income separately for social insurance treatment and for self-pay and other treatment. That single sheet settles both the enterprise tax and the consumption tax questions.

Summary

• For a private-practice doctor's individual business tax, both the income and expenses from social insurance medical care are excluded from the calculation, and 5% is applied to the remaining income.
• Medical practice falls under Type 3 business with a 5% tax rate, and the business owner deduction is ¥2.9 million a year. The blue-return special deduction cannot be used.
• Workers' compensation, mandatory auto insurance, pollution compensation, and normal childbirth are taxable under business tax but exempt from consumption tax.
• The simplified expense special provision requires social insurance medical income of ¥50 million or less and total revenue of ¥70 million or less. Even if income tax is reduced, business tax does not change.
• First, separate social insurance medical income from private-pay medical income in the financial statements, then check the 'Tax-exempt income, etc.' field on the second form.

Reference links (sources)

• Local Tax Act - business categories and exemption
• Act on Special Measures Concerning Taxation, Art. 26 - requirements for estimated expenses
• Consumption Tax Act, Appended Table 2 - exemption for workers' compensation and the rest
• Wakayama Prefecture, income calculation for medical practice enterprise tax - the apportionment ratio
• Tokyo Metropolitan Bureau of Taxation, individual enterprise tax - adding back the blue return deduction
• Tottori Prefecture, how to calculate enterprise tax for medical practice - the simplified formula
• Ministry of Finance, fiscal 2026 tax reform outline - no amendment
• NTA No.6201, exempt transactions - cosmetic surgery is taxable
• NTA No.6501, exemption from filing obligation - the ¥10 million test
• NTA No.1415, employment expense deduction - the one-half threshold
• NTA Q&A, occupational physician fees - salary in principle

Note: the calculations apply the statutes and the prefectural methods as this site reads them. Forms differ by prefecture. For an individual decision, ask a tax accountant or your prefectural tax office.