Pension Deferral: Take-Home Pay and the Break-Even Age

The short answer: the break-even age on a gross basis and on a take-home basis

Source: Japan Pension Service, "Deferred receipt of the old-age pension" [Japan Pension Service]. Take-home is an estimate for a single person aged 65 or over living in Tokyo's 23 wards with no income other than the pension, after the public pension deduction, the basic deduction, National Health Insurance premiums (including reductions), long-term care insurance premiums (by income bracket), income tax and resident tax

The gross break-even is simply "how long it takes the 42% uplift to make up the five years of pension you gave up", so it does not depend on the size of the pension: 81 years 11 months (5 ÷ 0.42 = 11.9 years). Work it out on take-home instead and the smaller the pension, the further back the break-even moves. Someone on 1.8 million yen who starts at 65 is exempt from resident tax and sits in the reduced brackets for National Health Insurance and long-term care premiums; deferring until the pension reaches 2.56 million yen takes them out of the exemption, and the premium reductions vanish with it.

Why take-home does not grow as fast as the gross: three reasons

1. The public pension deduction is mostly a flat amount. For people aged 65 or over it is a flat 1.1 million yen for pensions of 3.3 million yen or less, so it does not grow when the pension grows. At 1.8 million yen the taxable portion is 700,000 yen (39%); at 2.56 million yen it is 1.46 million yen (57%). Almost the whole of the increase lands in taxable income.
2. National Health Insurance and long-term care premiums rise with income. The National Health Insurance income levy (about 10% in Tokyo's 23 wards) is proportional to pension income, and the long-term care premium jumps with each income bracket — 0.69, then 1.2, 1.3 and 1.5 times the standard amount. Premiums are set on income before personal deductions are applied, so they bite harder than tax does.
3. You cross the line for exemption from resident tax. A single person aged 65 or over with a pension of 1.55 million yen or less (Tokyo's 23 wards and other grade-1 areas) is exempt from resident tax, and exemption brings a reduction of up to 70% on the National Health Insurance per-capita levy, cheaper long-term care premiums, a lower cap under the high-cost medical expense system and much else. Deferral that crosses the line strips all of it away at once.

The breakdown for a 2.4 million yen pension: starting at 65 and starting at 70

The gross goes up by 1.01 million yen but take-home by only 760,000 yen: a quarter of the increase disappears into tax and premiums. That erosion is what pushes the break-even age back. Start at 75 (gross 4.42 million yen) and the income tax rate rises to 10% while the National Health Insurance premium approaches its cap, so the erosion is larger still. For how pensions are taxed, see tax on pensions and the final return; for how the premiums are worked out, see calculating National Health Insurance premiums.

Watch out if your pension is small: the line where exemption from resident tax ends

A single person aged 65 or over is exempt from resident tax if pension income is 1.55 million yen or less (grade-1 areas such as Tokyo's 23 wards; about 1.52 million yen in grade-2 areas and about 1.48 million yen in grade-3 areas). For a couple, with the spouse as a dependant, the line is about 2.11 million yen. Exemption stacks up advantages: a reduction of up to 70% on the National Health Insurance per-capita levy, long-term care premiums at 0.285 to 0.69 times the standard amount, a high-cost medical expense cap of 8,000 yen a month for outpatient care, and eligibility for various benefit payments.

Someone on a 1.5 million yen pension who defers to 70 ends up at 2.13 million yen and loses the exemption. The gross rises by 630,000 yen a year, but once the lost advantages and the extra tax and premiums are counted the take-home gain shrinks to roughly 350,000 to 400,000 yen, and the break-even age passes 85. Counter-intuitive as it sounds, the smaller your pension, the less efficient deferral is. For the conditions, see what makes a household exempt from resident tax.

Conversely, if you work while waiting to claim, the tax and premiums for those years are set by your salary, and the deferred pension grows for the future. Note that under the 650,000 yen threshold for the in-work old-age pension, the portion suspended while you work is not eligible for the uplift.

The basic pension and the employees' pension can be deferred separately

The Japan Pension Service states that "the old-age basic pension and the old-age employees' pension can be deferred separately" [Japan Pension Service]. Seen through take-home pay, the following combinations are the practical ones.

• Take the employees' pension from 65 and defer only the basic pension. The spousal supplement attached to the employees' pension (about 410,000 yen a year until the spouse turns 65) is neither paid nor uplifted while you wait, so anyone entitled to it is usually better off claiming the employees' pension first.
• Place the pension you start receiving just under the exemption line. You cannot defer only part of the basic pension, but by choosing which of the two to take and from what age you can design the total against the 1.55 million yen line (single) or the 2.11 million yen line (couple).
• After 70 you can also claim a lump sum going back. If, once past 70, you decide you would rather have the pension from 65 in one payment, you are treated as having applied for deferral five years before the claim, and you receive the uplifted pension as a lump sum (deemed deferral five years back). The amount paid in one transfer is not, however, piled onto the income of the year you receive it. Back payments are taxed as income of each of the years to which the original payment dates belong [National Tax Agency, Income Tax Basic Circular 36-14(1)(b), note]. Instead, each of those past years is recalculated: income tax for five years, resident tax for three, and National Health Insurance or Late-Stage Elderly Medical premiums for two. How the figures come out is set out in lump-sum payment during the deferral wait and tax.

For the rules of deferral and early claiming themselves — the reduction rate, the fact that the choice cannot be undone, and the relationship with the disability pension — see early and deferred pension claims; for the order in which to draw a retirement allowance and iDeCo, see the money roadmap around retirement.

Frequently asked questions

Summary

• Deferring pension claims adds 0.7% per month. Claiming at 70 increases the amount by 42%; claiming at 75 increases it by 84%.
• Pension income is subject to tax and National Health Insurance/long-term care insurance premiums, so take-home pay does not increase as much as the gross amount.
• For someone with a ¥2.4 million pension, claiming at 70 brings the gross amount to ¥3.41 million and take-home pay to about ¥2.83 million. The break-even age shifts from 81 years 11 months to 83 years 8 months.
• The less pension income a person has, the bigger the loss from losing the resident tax exemption. For a single person aged 65 or older, the threshold is around ¥1.55 million in annual pension (e.g., in Tokyo's 23 wards).
• The basic pension and the employees' pension can be deferred separately. For those receiving a dependent pension allowance (kakyu nenkin), it is often more advantageous to start the employees' pension first.

Reference links (sources)

This article is based on the materials below. Take-home depends on your municipality's premium rates, its income brackets and whether you have dependants, so please check against the figures for the place where you live.

• Japan Pension Service, Deferred receipt of the old-age pension (0.7%, up to 84%, separate deferral, deemed deferral five years back)
• National Tax Agency, No.1600 Taxation of public pensions (the public pension deduction)
• MHLW, On adjusting the standard amount for long-term care insurance premiums (Social Security Council, Long-Term Care Insurance Committee, October 2025) (income brackets and multipliers)

Note: this article is general information. The amounts are estimates and vary with the municipality and the household. For an individual decision, check with a pension office or your municipality.