Tax-Saving Guide for Salaried Employees 2026: Furusato Nozei, iDeCo and Deductions

"Setsuzei" is not tax evasion. It is a way to get back what you overpaid

For salaried employees whose taxes are withheld from their pay, the word "setsuzei" (legal tax saving) can sound like something for other people. In fact it is simple: you apply to use the deductions and tax-free allowances the government has already set up. It is completely different from tax evasion, which means hiding the facts to avoid tax. If anything, employees are the ones who "lose out if they don't use it." That is because the tax on salary income is calculated roughly by the employer and paid in advance, so if you don't declare the deductions you were entitled to, the overpayment is never returned.

What makes it confusing is that each system has a different "where and when" for the paperwork. Some are finished through your employer's year-end adjustment, while others are not reflected at all unless you file a tax return yourself. If you combine several in the same year, where to submit documents and in what order gets tangled. Rather than just listing systems, this article is organized around the "forks in the procedure" where employees actually trip up, and sorts out which system to apply for where so you don't miss anything. Details of each system link to separate guides.

Does it apply "only to the excess" or "to everything once you pass the line"?

The key to the medical expense deduction is a single point: only the amount above the threshold counts. As covered in a later section, if you mix this up, you may feel that the whole amount you spent will come back. Even among "conditions you have to exceed," some work only on the excess and others work on the whole thing the moment you pass them, and shopping conditions split into exactly the same two kinds.

For example, free shipping above a certain amount is the type where the treatment of the whole order changes the moment you pass the line, so adding a little more makes it kick in. On the other hand, a rebate with a cap, or a discount that applies only to the part above a certain amount, is the type that works only on the excess, and adding more just hits a ceiling.

So when you are wondering whether to add a little more, check first which type the condition is, and the answer follows. If it is the type that works on the whole, it is worth moving up purchases you need anyway. If it is the excess-only type, adding more doesn't change much, so there is no reason to pile in things you don't need. Even when it is the same "meeting the condition," the meaning is completely different (→ How to think about buying to meet a condition).

Sorting the systems by "where you file" keeps you from getting lost

If you try to memorize them by name, there are too many and you give up. What really matters for an employee is one question: can this be handled by just handing paper to my employer, or do I have to file a tax return myself? Sort this out first and what to do at year-end becomes clear at once. The table below rearranges the main systems by where the procedure takes place.

Laid out like this, you can see that the zone where an employee "misses out unless they act" is surprisingly narrow. What is handled in year-end adjustment only requires filling in the form your employer hands out and attaching certificates. In contrast, the medical expense deduction, Furusato Nozei, and the first year of the housing loan deduction will not come back unless you take action yourself. The sections that follow dig into this "zone where you have to act" and the easy-to-miss order of combining systems.

Furusato Nozei: limits and how to choose after the points ban

Furusato Nozei is the easiest place for an employee to start. The mechanism is this: donate within your deduction limit and you receive return gifts from regions across Japan for an effective out-of-pocket cost of 2000 yen. The key point is that anything above your limit is just a plain donation (nothing comes back). The limit varies a lot with income and family structure, so be sure to find your own figure using each site's simulator.

Up to 5 municipalities, the One-Stop Special Rule is convenient

If you are an employee and donate to 5 municipalities or fewer in a year, you can use the "One-Stop Special Rule," which lets you skip filing a tax return. You send an application to the municipality with each donation. Note that in a year when you file a tax return for another reason, such as the medical expense deduction, the special rule becomes invalid and you must file again including the donations. If you plan to claim the medical expense deduction this year, it saves rework to include Furusato Nozei in the tax return from the start.

For a detailed look at limits and the procedure, see the Complete Guide to Furusato Nozei and Furusato Nozei tax calculation.

The moment the One-Stop Special Rule becomes invalid, and how to notice before it happens

Most Furusato Nozei mistakes come not from the donation itself but from not noticing that "the premise of the procedure collapsed partway" and carrying on into the new year. The classic case is filing a tax return for the medical expense deduction or the first year of the housing loan deduction after you have already sent One-Stop applications to every municipality. The moment you file a tax return, the One-Stop Special Rule becomes invalid for all donations at once, and if you forget to enter the donation deduction on the return, the deduction for everything you donated disappears. Don't think you are safe just because you submitted the special application. The right order is to decide first whether you will file a tax return this year, and then donate.

The next most common mistake is how you count municipalities. The One-Stop Special Rule is limited to five municipalities, but this counts municipalities, not the number of donations. Donating three times to the same city is still one municipality, but you must submit an application each time. Conversely, scattering small donations on impulse can easily push you over the municipality limit.

Misestimating the limit is another persistent mistake. The deduction limit is tied to taxable income, so if the housing loan deduction starts working in the second half of the year, you raise your iDeCo contributions, or your income drops because of childcare leave, the limit ends up lower than expected. The housing loan deduction in particular is subtracted directly from the tax amount, so having already reduced income tax and resident tax can narrow the room left for Furusato Nozei to give back.

Also watch for mismatched names. The donation is not deductible unless it is made in the name of the person who has the income. If you donate with a credit card in your spouse's name, some municipalities may refuse it because the names do not match, or accept it but not allow the deduction. Matching the card holder's name with the donor's name is enough to prevent this.

Deductions have set "deadline months": counting back through the year

Unlike shopping sales, tax-saving systems have no price swings; instead, only the deadlines are strict. Whether you benefit depends almost entirely on when you act. Roughly counting back through an employee's year will help you miss less.

What is most easily overlooked in this calendar is the resident tax determination notice in early summer. Whether your Furusato Nozei deduction has been reflected can only be seen here. Check once whether the total donation minus the 2,000 yen out-of-pocket amount roughly appears in the tax credit column for resident tax, and you can catch the accident of the One-Stop Special Rule having been invalidated. If you notice, there may still be a chance to redo the procedure for that year.

Because of financial institutions' cutoff dates, an iDeCo contribution increase "starting this month" is not reflected right away. If you want to use up this year's contribution limit, you need to act in autumn. In some cases you can choose something close to annual payment (a setting to contribute in a lump sum in December), but this also requires advance notification.

Document formats and identity verification to check before submitting

In deduction procedures, even if the content is correct, your filing will be sent back if the document format does not meet the requirements. Just as you measure before buying, there are conditions worth checking in advance.

My Number matters

The One-Stop Special Rule application requires your My Number and an attached identity verification document. If you have a My Number Card, one copy of the front and back is enough. If you don't, you need a notification card or a certificate of residence showing your My Number, plus a copy of an ID such as a driver's license. Each municipality has its own envelope, so the more places you donate to, the more copies you need. Having a card makes this much easier.

Certificates: original or electronic?

For a long time, the life insurance premium deduction certificate and the iDeCo small business mutual aid contribution payment certificate had to be submitted as paper originals. More companies now accept electronic data, but whether yours does depends on your employer's year-end adjustment system. A mismatch can happen where you set up electronic delivery but your company only accepts paper. You can often switch the issue format on the insurer's member page, so it is reassuring to check your employer's method before autumn.

Medical expenses are totaled on a "statement" form

For the medical expense deduction, you do not submit a stack of receipts. You total them on a statement form. The medical expense notice from your health insurance can save you some entries, but the period covered by the notice may end partway through the year, and you may have to add the rest yourself. Even though you don't submit receipts, you are required to keep them at home for a set period.

iDeCo and NISA: an "income deduction" and a "tax exemption" are different things

iDeCo and NISA are often lumped together as "tax-advantaged investing," but they work in completely different directions. If you start without separating them, you may stumble with "this isn't the tax saving I expected," so it is worth understanding them clearly apart.

In short, iDeCo "lightens the tax before you pay it (income tax and resident tax)," while NISA "removes the tax on profit after it has grown", so they work at opposite points in time. With iDeCo, taxable income drops in the year you contribute, so declaring the deduction in year-end adjustment lightens that year's burden. The biggest caution, however, is that you generally cannot withdraw until age 60. If you put in money you plan to use partway, such as education costs or a down payment on a home, you will be stuck.

NISA is more a "tax benefit" than "tax saving," and its tax-free advantage takes effect when you make investment gains. Since both are investments, the principal is not guaranteed. For how to choose between them, see Differences between NISA and iDeCo and how to use them; for opening an account, see Getting started with NISA and online brokers; for how iDeCo is paid out, see iDeCo tax savings and payout.

iDeCo, NISA, corporate DC and insurance: the same "saving" works differently

Even when the purpose, saving for retirement, is the same, the tax effect is entirely different. Who it suits changes depending on whether it lowers this year's tax through an income deduction or only makes investment gains tax-free.

Sorting by your situation

• If you have solid taxable income and money you won't need for a while, iDeCo or matching contributions, where the income deduction works, come first. The higher your tax rate, the bigger the effect.
• If you plan to buy a home or pay for education within a few years, NISA, which you can cash out at any time, is more realistic than iDeCo, which you can't withdraw from.
• During periods when the housing loan deduction has brought your income tax close to zero, there is less room for iDeCo's income deduction to work. There is a mechanism that shifts the portion you can't fully deduct to resident tax, but it has limits, so putting NISA first during this period is also a valid view.
• If you are someone with a corporate DC plan, whether matching contributions and iDeCo can be combined is set by the plan rules. In many cases you can choose only one, and on fees, matching contributions by payroll deduction tend to be more favorable.

Because private annuity insurance has a deduction cap, the idea of "increasing premiums to save tax" doesn't really work. If you already have it, you should definitely submit the certificate, but if you would be newly joining just for the deduction, putting the same money into iDeCo normally gives a larger income deduction. It is better to decide based on whether you need the coverage.

Medical expense deduction: the key point that only the "excess" counts

The medical expense deduction is a system where if the medical expenses you paid in one year (January to December) exceed a set amount, the excess can be subtracted from your income. A common misunderstanding is that "the full amount of medical expenses you paid comes back." In reality only the part above the threshold counts, and what comes back is a further portion of that (the deduction amount multiplied by your tax rate). If you mix this up you tend to be disappointed that "it's less than I thought," so get it straight at the start.

Whether the combined family total exceeds the threshold is the dividing line

What matters is that you can combine medical expenses of family members who share your living expenses. It is not unusual for a person alone to fall short of the threshold but exceed it when the spouse, children and even parents living elsewhere are added in. Transportation costs for hospital visits may also count, and there are detailed conditions on what is eligible. For costs you are unsure about, it is safer not to include them on your own judgment and instead check with National Tax Agency information or the tax office.

• Keeping receipts and statements is a prerequisite: filing requires a full year's totals. If you collect them in an envelope from the start of the year, year-end will not be a problem.
• Choosing against the Self-Medication Tax System: in a year mostly of over-the-counter drugs, the separate allowance can be more favorable, and you choose one or the other.
• The only procedure is a tax return: it cannot be handled in year-end adjustment, so in a year that may qualify, prepare to file a tax return.

Housing loan deduction: the trap of needing a tax return in the first year only

For employees who bought a home with a housing loan, what greatly affects the tax burden is the housing loan deduction (special deduction for housing loan balances). This is not an "income deduction" subtracted from income, but a "tax credit" subtracted directly from the calculated tax. Because the impact is large, the requirements and conditions for eligible homes are detailed, and overlooking them means missing out for years.

What trips employees up most is the order of procedures. In the first year you cannot receive it through year-end adjustment, and you must file a tax return yourself. If you leave this alone assuming "my company will do it," you lose that year's deduction. From year 2 onward it can be included in year-end adjustment with documents handed out by your company, so once you get past the extra step in the first year, it becomes easy. Conditions for eligible homes and how the deduction works are covered in Taxes on your home.

Deductions completed in year-end adjustment alone: forgetting to submit is the biggest waste

Because no tax return is needed, the group of deductions completed in year-end adjustment is easy to overlook. All you do is fill in the form your company hands out and attach certificates, yet skipping that small effort and missing the deduction is the biggest waste. The first step is to keep the various "deduction certificates" that arrive in autumn rather than throwing them away.

• Life insurance premium deduction: part of the premiums for life insurance, medical insurance, private annuities and the like becomes an income deduction. Copy the deduction certificate that arrives around October and November onto the form. If you are concerned about overlapping coverage, check it together with a review of your insurance.
• Earthquake insurance premium deduction: the earthquake insurance portion bundled with fire insurance is eligible. The certificate is often enclosed with your fire insurance documents, so be careful not to overlook it.
• iDeCo contributions: declared in year-end adjustment as a small business mutual aid premium deduction. If your contributions are not deducted from your pay, you need the payment certificate.
• Dependent deduction and spouse (special) deduction: a deduction based on family structure. In a year when a family member's income changes, update what you declare.

With these, everything depends on "whether you kept the certificates" and "whether you left out any field on the form." There is no hard judgment involved; it is a matter of preparation and copying. Just the habit of keeping the envelopes that arrive by mail in autumn in one place greatly reduces what you miss.

Who needs to file a tax return, and what to do at year-end

It is commonly thought that "employee means no tax return needed," but in reality there are people who benefit from filing and people who must file. Knowing early which one you are helps you avoid the rush in the new year.

• A year when medical expenses exceed the threshold: if the family total exceeds a set amount, you can receive the deduction through a tax return.
• The first year after buying a home: a tax return is mandatory for year 1 of the housing loan deduction.
• Donating to 6 or more municipalities through Furusato Nozei, or forgetting to submit the special application: in this case One-Stop cannot be used and you file a tax return.
• Income other than salary, such as a side job: side income above a set amount is subject to filing. Check Cases where a tax return is needed for when it applies.

In a year when you file a tax return, the point is that the procedure becomes one when combined with the systems handled by year-end adjustment. For example, if you file for the medical expense deduction, putting the Furusato Nozei donations on the same return saves doing things twice. Conversely, if you assume "year-end adjustment took care of everything," you overlook deductions you should have acted on yourself. Deciding once in autumn whether "this is a year I need to file a tax return" is the best way to avoid missing out.

What to prepare first to use the systems, and what you don't really need

The deduction systems themselves are free, but there are a few things worth preparing first so you don't get stuck. Conversely, there are also things often recommended that are low priority.

What to prepare first

• My Number Card. It is the entrance to nearly everything: identity verification for the One-Stop Special Rule, electronic filing, and getting your medical expense notice. Issuance takes several weeks, so if you apply only when you need it, you will be too late.
• A credit card and bank account in your own name. They are used for matching names in Furusato Nozei, for receiving refunds, and for iDeCo withdrawals. Besides your salary account, deciding on one account to gather deduction-related deposits and payments speeds up your totals.
• A way to keep medical expense records. Searching for receipts after the year has changed is the hardest part. Pick one envelope and drop receipts in at every hospital visit. That alone changes the burden of preparing the statement. Transportation costs (fares on public transport) may also be eligible, so noting the date and route lets you total them.
• Keeping your withholding slip. It no longer needs to be attached when filing a tax return, but you always need it as the source for the amounts you copy. When it is handed out after year-end adjustment, decide on the spot where to keep it.

Lower priority

• Paid tax return software. For salary income plus the medical expense deduction or Furusato Nozei, the National Tax Agency's tax return preparation corner is enough. It is fine to consider it once you need bookkeeping for a side job.
• An IC card reader. Not needed if you have a smartphone that supports the My Number Card. First check whether the device you have supports it.
• Buying insurance just for the deduction. As mentioned above, the deduction has a cap, and the amount returned is limited relative to the premiums you pay. Decide based on whether you need the coverage.

Terms on the withholding slip and tax return: where to look to compare

In talk of deductions, the calculation will not match if the definitions of terms drift. If you at least understand how the following terms relate, you won't get lost at the simulator's input fields.

Two pairs that are easy to confuse

Income deduction and tax credit. An income deduction reduces taxable income, so its effect shrinks to the share of your own tax rate. A tax credit is subtracted directly from the tax itself, so the face amount takes full effect. The medical expense deduction and life insurance premium deduction are the former; the housing loan deduction is the latter. This is the difference behind "the same deduction amount but a different amount coming back."

Refund and tax reduction. What comes back through year-end adjustment or a tax return is income tax you already overpaid. Resident tax works by lowering the next fiscal year's tax amount, so it is not cash returned to your hands but lighter monthly withholding. This is why most of the effect of Furusato Nozei appears on the resident tax side.

Fields in the simulator that cause confusion

• "Annual income" or "income". The simple version on Furusato Nozei sites usually asks for annual income, while the detailed version copies the fields from your withholding slip. The detailed version is more accurate, and people with iDeCo or a housing loan deduction should use it.
• Social insurance premium amount. Use the "amount of social insurance premiums, etc." on the withholding slip as it is. Multiplying the monthly amount on your pay slip by twelve will be off because of the bonus portion.
• Category of dependent relatives. Some categories change the deduction amount by age, so simply entering a head count may throw off the limit.

Once you know how to read the numbers, you can explain "why this limit" yourself instead of just accepting the simulator's result. Even in a year when the system changes, where you look does not change much.

Frequently asked questions