ISO週・会計四半期コンバーター - 週番号と会計年度
日付からISO週番号/年を計算し、カスタムの会計開始月で会計年度と四半期を算出します。
Keywords
ISO週番号, 週年, 会計四半期, 会計年度, ISO週 変換
ISO week date assigns week numbers consistently across years, while fiscal calendars group dates into business reporting periods. This page converts dates to ISO week/year and computes fiscal year and quarter.
What is ISO week?
ISO‑8601 defines weeks starting on Monday; Week 01 is the week with the first Thursday of the year. A date like 2025‑01‑01 may belong to ISO week 2025‑01 or even the last week of the previous ISO week year depending on the calendar alignment.
Fiscal calendars
Organizations adopt fiscal years that don’t start in January—e.g., April or October—to match planning cycles. Quarters divide the year into Q1–Q4 from the chosen start month (for example, a fiscal year starting in April has Q1: Apr–Jun).
Example
Given 2025‑04‑02 with a fiscal start month of April, the tool reports Fiscal Year 2025, Quarter Q1. For ISO week, the same date might be ISO Week 2025‑14 with a Monday–Sunday range shown for clarity.
Standardized week and fiscal calculations prevent reporting mismatches. Use explicit labels (ISO week year, week number, fiscal year) in analytics and exports.
ISO週・会計四半期コンバーター
ISO週/年、週の範囲、会計四半期を求める