Resident tax

Resident tax (住民税) is the part of the picture most take-home calculators quietly get wrong. It is not withheld from this month’s pay. It is a separate tax, levied on the prior year's (2025) income, billed june→may — so the resident tax leaving your pay right now was set by last year’s income, and this year’s income sets next year’s bill. This tool therefore shows resident tax as a labelled estimate beside the breakdown, never folded into the this-month bar.

Why it lags a whole year

Your municipality assesses resident tax on the prior calendar year’s income and bills it from June to the following May. There is no monthly reconciliation the way income tax has; it is an annual bill, spread across twelve months of the following year. Because we cannot know your actual prior-year income, the calculator estimates resident tax on the income you enter as a proxy for the prior year — an estimate, clearly, and one that will be off in any year your income changed sharply.

How the bill is built

Resident tax has two parts. The income levy (所得割) is 10% of the prior year’s taxable income — split between a municipal portion and a prefectural portion that together make that rate. On top of it sits the per-capita amount (均等割), a flat ¥5,000 a year that includes the national forest-environment component. A small adjustment credit (調整控除) is applied and the result is floored at zero. This calculator applies that credit as a flat ¥2,500 rather than computing it from your own deduction differences — the simplification was already disclosed further down, and this is the number it uses.

Crucially, the resident-tax basic deduction is ¥430,000 — and this is not the income-tax basic deduction (which the 2025 reform lifted to as much as ¥950,000). The reform changed the income-tax basic deduction only; resident tax was left untouched, so the two are computed on different bases and must not be conflated. The same gap runs through the dependent deductions: the resident-tax specified-dependent deduction is ¥450,000 against the income tax’s ¥630,000.

First-year hires pay ¥0 — with a caveat

Someone in their first year of work with no prior-year income owes ¥0 resident tax, because there is no prior year to assess. A toggle covers that case. But the ¥0 holds only when prior-year income was actually nil — it is not a blanket “year one is always exempt,” and someone who worked, freelanced or earned in the prior year does owe it.

Two honest limits: the calculator does not apply the municipal non-taxation floor (非課税限度額), so it slightly over-estimates resident tax for the very lowest earners; and the adjustment credit is modelled at its standard value rather than derived from your exact deduction gap. Both are disclosed, and no figure here carries the reviewer’s sign-off — treat the resident-tax line as a rough lagged estimate, not a number to budget against.