Income 税額 calculator (UKとUS)

Income tax calculator (UKとUS)の使い方

何を計算するか、いつ使うか

Estimates income 税額、National Insurance (UK)またはSocial Security、Medicare (US)、your effective、marginal rates,とa band-by-band breakdown.

使い方の手順

1. Choose where you 給与 税額: England/Wales/Northern Ireland, Scotlandまたはthe US.
2. Enter your income 単位 年 before 税額.
3. Add pensionまたはthe UK, a student loan plan.の401(k) contributions paid before tax and,
4. Read the 税額、take-home 給与、marginal 利率.

各入力項目の意味

• Income – Gross 給与個でthe 年.
• Filing status (US) – Sets the standard deductionとbrackets.
• Pension 有給 before 税額 – Reduces taxable income.
• Student loan plan (UK) – Plan thresholdsとrates decide repayments.

結果の読み方

• Income 税額 – each band.のtax The 合計
• Effective 利率 – Income 税額 ÷ income.
• Marginal 利率 – 合計income, including National InsuranceまたはFICA. tax on the next単位
• 税額 by band – How much was taxed 適用 1個あたり 利率.

計算式

UK: taxable income = income − personal allowance (12,570、reduced by 1個でevery 2 over 100,000). Taxはtaxable income, 40% to 125,140 20% on the first 37,700です、England; Scotland uses six bands. National Insuranceの45% aboveは8% between 12,570ですと50,270と2% above. US: taxable income = income − standard deduction, taxed in 10%〜37% brackets.

計算例

12,570 A UK taxpayer earning 50,000 has a personal allowance、so 37,430はtaxable at 20%です個でtax. National Insurance 7,486は2,994, take-home payは39,520ですです、the marginal rateは28%.です

前提と限界

• UK: standard 税額 code, いいえ other income, いいえ Marriage Allowanceまたはbenefits.
• US: federal 税額 only with the standard deduction. State taxes、単位数、itemised deductions are excluded.
• Pension contributions are treated as 有給 before 税額 but not before NI.

よくある間違い

• Applying the top rate〜each bandのall income. Only incomeはtaxed 適用 that band’s 利率.です
• Forgetting National InsuranceまたはFICA.

よくある質問

Dated rules: UK tax year 2026から2027（6 April 2026から5 April 2027）、開始 GOV.UK. Rates、thresholds change each year、so check GOV.UK before relying on a figure. Dated rules: US federal figures個でtax year 2026 (IRS Rev. Proc. 2025-32、IRS notices). These calculators are estimates個でplanning, not tax advice.

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