Business days calculator, and an MCP server that counts holidays too.
DayCount is a business days calculator your AI assistant can call. Language models are unreliable at date arithmetic; DayCount does it exactly: working days between two dates, the date a number of business days away, whether a date is a working day, and public holidays for about 200 countries and their regions, each with the holidays and weekends it skipped. It knows the weekend is Friday and Saturday in much of the Middle East, and that some holidays begin at sunset.
01Free business days calculator
Business days calculator, for any weekend.
Count the working days between two dates, or add business days to a date, with the weekend your country uses. DayCount, the MCP server below, also takes public holidays off for about 200 countries.
Counted from the start date up to but not including the end date. Public holidays are not taken off here; DayCount, the MCP server below, takes them off for about 200 countries.
02See it work
DayCount, in real use.
5 screens from real calls to DayCount. Every value shown is what the tool returned; click a screen to open it full size.
03How it works
Dates done by counting, not by guessing.
Language models predict text; they do not count days. DayCount walks the calendar one day at a time, skips the country's weekend and holidays, and says what it skipped. Three business days after Tuesday 22 December 2026 in Mauritius:
- Tue22Start
- Wed23Day 1
- Thu24Day 2
- Fri25Christmas Day
- Sat26Weekend
- Sun27Weekend
- Mon28Day 3, the answer
04Weekends
Weekends around the world.
Saturday and Sunday is the most common weekend, not the only one. DayCount uses each country's usual weekend; the United Arab Emirates moved to Saturday and Sunday in 2022, while Saudi Arabia keeps Friday and Saturday. You can always pass your own.
05Working days
How many working days there are in 2027.
From count_business_days for the whole of 2027 in each country, public holidays only. Pass a region for state and provincial holidays, or holiday_types to count bank or school holidays too.
| Country | Working days in 2027 | Weekend days | Public holidays on working days |
|---|---|---|---|
| India | 258 | 104 | 3 |
| Germany | 256 | 104 | 5 |
| Australia | 255 | 104 | 6 |
| Singapore | 255 | 104 | 6 |
| United Kingdom | 254 | 104 | 7 |
| France | 254 | 104 | 7 |
| Mauritius | 252 | 104 | 9 |
| United Arab Emirates | 252 | 104 | 9 |
| Saudi Arabia | 252 | 105 (Friday and Saturday) | 8 |
| United States | 249 | 104 | 12 |
06For developers
A public holidays API your assistant can call.
DayCount is an MCP server, so assistants call it directly. It is also a plain JSON-RPC endpoint over HTTPS, so you can try a call from a terminal. This one is real; the reply is cut after the first holidays.
curl https://daycount.dudelemon.cloud/mcp \
-H 'Content-Type: application/json' \
-H 'MCP-Protocol-Version: 2025-06-18' \
-d '{"jsonrpc": "2.0", "id": 1,
"method": "tools/call",
"params": {
"name": "list_holidays",
"arguments": { "country": "MU",
"year": 2027 } } }'{
"country": "MU",
"place": "Mauritius",
"year": 2027,
"count": 15,
"holidays": [
{ "date": "2027-01-01", "weekday": "Friday",
"name": "New Year’s Day", "type": "public" },
{ "date": "2027-01-02", "weekday": "Saturday",
"name": "New Year Holiday", "type": "public" },
{ "date": "2027-01-20", "weekday": "Wednesday",
"name": "Thaipoosam Cavadee", "type": "public" },
...07Install
Install DayCount.
DayCount runs on our servers, so there is nothing to download. Add its address to your assistant, and its 6 tools appear the next time you start a conversation.
claude mcp add --transport http daycount https://daycount.dudelemon.cloud/mcpRun in your terminal. Add --scope user to make it available in every project.
08Tools
Its tools, and what each returns.
list_holidays- A country’s or region’s holidays for a year, with date, weekday, English name and type.
is_business_day- Whether a date is a working day, and if not, the weekend or the holiday that makes it one.
add_business_days- The date a number of business days before or after a start date, with the holidays skipped.
count_business_days- Working days between two dates, with the weekends and holidays in the range.
date_difference- Days, weeks, months and years between two dates, with ISO weeks and day of the year.
find_country- Country codes, each country’s usual weekend and its region codes.
09Ask in your own words
Say what you need. DayCount does the exact part.
You do not call DayCount’s tools by name. Ask your assistant, and it calls them when the question needs live, exact data.
- What date is 10 business days from today in Germany?
- How many working days are there in March in Mauritius?
- Is 27 November a working day in the UAE?
- List the bank holidays in Scotland next year.
10Works well with
Related tools.
FAQ
DayCount, answered
Anything we have not answered here, ask us directly. A senior engineer replies.
Where does the holiday data come from?
From the open date-holidays project (data under CC BY-SA 4.0), which covers about 200 countries and their states and provinces. Holidays set by the moon or announced each year can move by a day, so check the official notice for legal deadlines.
Can I count bank holidays or school holidays?
Yes. By default only public holidays count as days off; pass holiday_types to add bank, school, optional or observance days.
What if our weekend is different?
Each country uses its usual weekend, and you can pass your own, for example Friday only or Saturday only.
Is DayCount free?
Yes. DayCount is free and needs no account or API key.
How do I install DayCount?
Add https://daycount.dudelemon.cloud/mcp to your assistant as a remote MCP server. In Claude Code run claude mcp add --transport http daycount https://daycount.dudelemon.cloud/mcp; in the Claude apps add it as a custom connector with no sign-in; in Cursor or VS Code add it to mcp.json.
Does DayCount know regional holidays?
Yes. Pass a region code, such as SCT for Scotland, BY for Bavaria or CA for California, and the regional holidays are added to the national ones.