WORKDAYS Help Documentation

A complete guide to the business days calculator, from the first count to the exported history.

Last Updated: October 7, 2026

1. Getting Started

1.1 What you need

• A modern browser (Chrome, Edge, Firefox, Safari or Opera) with JavaScript enabled, on a computer, tablet or phone
• Site data allowed for zerodataupload.com, so your work week, holidays and history are kept between visits
• Two dates, or one date and a number of days

1.2 The layout

The tool is one page with six tabs in the toolbar: Days between, Add/Subtract, Deadline, Batch, Leave and Settings. To the left of the tabs, the status pill shows the work week and the holiday calendar in force, for example "Mon to Fri · 5 days a week" and "United States holidays · 2 custom holidays"; every calculator follows them. Each tab shows its cards; on a tablet or phone the cards stack and the tabs sit in two rows.

1.3 First steps

1. Open Settings and choose your country under Public Holidays, so its holidays are skipped.
2. Check the Work Week: Monday to Friday is the default; pick another preset or set each day to full, half or off.
3. Add the holidays only your company takes under Custom Holidays.
4. Go back to Days between: the result for today to a month from now is already there, and it updates as you change the dates.

2. Days Between

2.1 Counting

Pick a Start date and an End date, or press a preset chip: This week, This month, This quarter, This fiscal year (from the month set in Preferences), This year, Next 30 days or Next 90 days. The result updates on its own when a date changes; Calculate working days counts again and adds the result to the history. Swap dates exchanges the two fields. If the end date is before the start date, the dates are swapped for the count and a notice says so.

2.2 The result

The big number is the working days. The line under it gives the two dates with their weekdays, the calendar days in the span and, when one of the include switches is off, how many days were counted. Four tiles show the working days, the days off (days that are off in your work week), the holidays (public and custom holidays on working days) and the half days. The Breakdown table shows each category as a count and as a share of the days counted.

2.3 The calendar

The Calendar card shows the month of the start date, with every day coloured: green for a working day, grey for a day off, red for a holiday, amber for a half day. The selected range has a tinted edge, the start and end dates a brand-coloured border, and today a dot. Hover a holiday to see its name. The arrows move a month at a time and Today jumps back. Click a day to set the start date, then click another to set the end date; clicking again starts over.

2.4 Holidays in the Range

When the range contains holidays, this card lists them with their date, weekday and source (the country or Custom). A holiday that falls on a day off is marked "already a day off"; it is listed for information and does not change the count.

3. Add or Subtract Business Days

Enter a Start date and a number of Business days; a negative number goes backwards. The chips set +5, +10, +20, +30, −5 and −10 and calculate at once. The result is the date reached, its weekday, and how many calendar days from today it is, with tiles for the working days moved, the calendar days passed, and the days off and holidays that were skipped.

The How It Counts card beside the form repeats these rules and names the work week and the holiday calendar in force, so the result can be explained to anyone.

4. Deadline and Latest Start Date

4.1 Deadline From a Start Date

The same calculation as adding business days, laid out for deadlines: a Start date, the Working days required, and chips for the common deadlines (1 week = 5, 2 weeks = 10, 3 weeks = 15, 20, 30, 45, 60 and 90 working days). The result shows the deadline date, its weekday, how many calendar days away it is, and the tiles.

4.2 Latest Start Date for a Deadline

Enter the Deadline and the Working days needed before it; Find the start date moves backwards by that many working days. The deadline day itself is not counted, so this is the exact reverse of the deadline calculation: 30 working days from the start lands on the deadline, and 30 working days before the deadline lands on the start.

5. Batch

Several date ranges at once, up to fifty. Each row has a Label (optional; Range 1, Range 2 and so on otherwise), a Start date and an End date, and a cross to remove it. Add a range adds a row, Calculate all counts every complete row with the same rules as Days between (including the two include switches) and Clear starts over with two empty rows. The result shows the total working days and a table with, per range, the days counted, the days off, the holidays and the working days. Download as CSV writes the table to a file, with the half days as an extra column.

6. Leave

Enter the First day away and the Last day away; both are included whatever the preferences say, because a holiday is a span of days. Calculate leave days gives the leave days to book (the working days in the span) and tiles for the days away, the free days off, the free public holidays and the days saved. The card beside it lists the holidays that fall in the period. Move the dates a day or two and compare: ending a trip on a Sunday instead of a Friday, or starting it on a public holiday, changes nothing in the days away and saves leave.

7. The Work Week

Under Settings, the Work Week card has four presets: Mon to Fri, Mon to Sat, Sun to Thu and Half Saturday (Monday to Friday full, Saturday half). Below them, each weekday has its own choice of Full day, Half day or Off; change any of them and the preset shows as Custom. A half day counts as 0.5 of a working day in every calculator. The status pill in the toolbar updates at once, and so do any results on the other tabs.

8. Public Holidays

8.1 Choosing a country

The Public Holidays card has a country list: the United States, the United Kingdom, India, Canada, Australia, Germany, France, Japan, Singapore and the United Arab Emirates, or "No country calendar". Choosing one loads its holidays into every calculator and shows the list for the current year, with arrows to browse other years. A note under the list says which holidays are covered for that country and how substitute days are handled.

8.2 How the dates are made

The holidays are computed by rule for any year: fixed dates (Christmas), nth weekdays (the fourth Thursday of November for Thanksgiving, the last Monday of May for the Spring Bank Holiday), the days around Easter from the Gregorian Easter computus (Good Friday, Easter Monday, Ascension, Whit Monday), the equinox days of Japan, and each country's substitute-day rule when a holiday lands on a weekend. Holidays that follow a lunar calendar (Holi, Dussehra and Diwali in India; Chinese New Year, Vesak Day, Hari Raya Puasa, Hari Raya Haji and Deepavali in Singapore; Eid al-Fitr, Arafat Day, Eid al-Adha, the Islamic New Year and the Prophet's Birthday in the United Arab Emirates) come from a table for 2025 to 2027, with the 2027 dates marked "estimated" until the official lists are published. In other years those holidays are missing and the note says so.

8.3 Substitute days

• United States: a Saturday holiday is observed on the Friday before, a Sunday holiday on the Monday after; New Year's Day can therefore be observed on 31 December of the previous year.
• United Kingdom, Canada, Australia: a weekend holiday moves to the next weekday that is not already a holiday, so Christmas on a Saturday is observed on Monday 27 and Boxing Day on Tuesday 28. Anzac Day is not moved.
• Japan: a Sunday holiday moves to the next free weekday, and a weekday caught between two holidays becomes a citizens' holiday (as on 22 September 2026).
• Singapore: a Sunday holiday is observed on the Monday after.
• Germany, France, India, United Arab Emirates: holidays are not moved.

9. Custom Holidays

The Custom Holidays card takes a Date, a Name and a Type (Full day or Half day). Add holiday puts it in the list, sorted by date, and into every calculation; the cross on an entry removes it, Remove all clears the list after a confirmation. One custom holiday per date, up to 200. A custom holiday takes precedence over a public holiday on the same date, so a custom half day on a public holiday counts as half a day.

10. Preferences

• Date format: how dates are shown in results, lists and the history: 7 Oct 2026 (the default), day first with slashes, month first with slashes, or year first with hyphens. The date fields themselves follow the browser's own format.
• Fiscal year starts in: the month the This fiscal year preset starts from (April by default; January, July and October are common elsewhere).
• Count the start date and Count the end date: whether those two days are included in Days between and Batch. Both are on by default. They do not affect Add/Subtract, Deadline or Leave, which have fixed rules.

11. Saved Configurations and Backup

11.1 Configurations

A configuration is the work week, the country and the custom holidays together under a name. Type a name such as "US office" or "India IT" and press Save; the list shows each configuration with its country, the number of custom holidays and the date it was saved. Load replaces the current week, country and custom holidays with the saved ones (the preferences and the history are left alone); the cross deletes a configuration after a confirmation. Up to twenty are kept, and names must be unique.

11.2 Backup

Export everything downloads one file with the settings, the saved configurations and the history. Restore a backup reads such a file and, after a confirmation, replaces everything the tool holds with its contents. Use it to move to another browser or computer, or as insurance against cleared site data. Files that are not WORKDAYS backups are refused.

12. History and Printing

The History card lists the last fifty calculations started with a button or a preset, from every tab, newest first, each with its kind, its inputs, its result and the time. Results that update on their own as you change a date or a setting are not added. Download as CSV writes the whole history to a file; Clear empties it after a confirmation; Print opens the browser's print dialog with only the open tab's cards on the page (choose "Save as PDF" there to keep a copy).

13. Keyboard Shortcuts

• Alt+1 to Alt+6: switch to Days between, Add/Subtract, Deadline, Batch, Leave and Settings
• Enter in a field or on the page: calculate in the open tab
• Left and Right arrows on the tabs: move between them
• Alt+T: toggle the light and dark theme
• Esc: close a confirmation window

14. What Is Remembered

The browser's storage on this device holds, under the tool's own name, the work week, the country, the custom holidays, the date format, the fiscal year start, the two include switches, the saved configurations and the history. The dates typed into the calculators are not kept between visits: each visit starts with today and a month from now. The light or dark theme is shared with the rest of the site.

15. Troubleshooting

• The count looks wrong. Read the status pill: it names the work week and the holiday calendar in force. Then look at the calendar and the Holidays in the Range card on Days between; a country left over from another job, a custom holiday, a half day or an include switch turned off is nearly always the reason.
• A holiday I expect is missing. Lunar holidays are listed for 2025 to 2027 only; one-off and state holidays are never computed. Add it under Custom Holidays.
• A holiday on a Saturday did not reduce the count. Saturday is off in your work week, so the day was already off; countries with substitute days have the substitute listed on the weekday instead.
• The result ends in .5. A half day in the work week or a custom half-day holiday is in the range.
• Nothing happens when I press Calculate. A notice at the bottom right says what is missing: a date, a number of days, or a work week with at least one working day.
• My settings vanished. Site data was cleared, or this is a private window or another browser. Restore the backup file if you have one.

16. Support