What date format should I enter?

Enter a valid date, such as 2026-07-25.

What does the ISO week number represent?

It follows ISO 8601, where week 1 is the week containing the year's first Thursday.

Which fiscal calendars are supported?

The tool supports standard calendar quarters, 4-4-5, 4-5-4, and 13-week calendars.

Can I choose a fiscal year start month?

Yes. You can select any month from January through December.

What information does the tool return?

It returns the ISO week number, day of year, Julian Day, fiscal quarter, and fiscal-quarter boundaries.

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ISO Week Number and Fiscal Quarter Anchor Finder

Convert any date to ISO 8601 week number, day-of-year, Julian Day, and fiscal-quarter boundaries (4-4-5, 4-5-4, 13-week, or standard).

Details

What this tool helps you do

Business reporting often runs on fiscal calendars that don't align with calendar months. This tool computes the ISO 8601 week number (week 1 = the week with the year's first Thursday), the day-of-year ordinal, the Julian Day number (for date math), and the fiscal quarter a date falls into under four common calendars: 4-4-5 retail, 4-5-4 NRF retail, 13-week equal, and standard calendar quarters — each with a configurable fiscal-year start month. Great for SaaS finance, quarterly reviews, and project planning.

Execution

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Prepared example runs

Click an example to fill the form automatically. File inputs still need an upload.

2 examples

ISO week and fiscal quarter for 2026-07-25

A mid-summer date analyzed under standard calendar quarters — ISO week 30, day 206, Q3.

{
  "type": "text"
}

4-4-5 retail fiscal quarter (FY starts in July)

A September date in a 4-4-5 retail calendar whose fiscal year begins in July — lands in Q1 of the new FY.

{
  "type": "text"
}

Inputs

Set the required fields, then run the tool.

3 options

SettingsAdjust formats, ranges, numbers, and modes.3

DatedateRequiredFiscal CalendarselectRequiredFiscal Year Start MonthselectOptional

Result

Ready for a run

Run the tool to preview files, text, structured data, or streamed output here.

Samples

ISO Week Number and Fiscal Quarter Anchor Finder

What this tool helps you do

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Prepared example runs

Inputs

Result

Examples that match this tool

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Prepared example runs

Inputs

Result

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Key facts

Overview

When to use

How it works

Use cases

Examples

1. Retail sales period lookup

2. Finance reporting date check

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