# Date Calculator MCP server

> Count days between dates, add or subtract time from a date, and look up public holidays by country and region.

- Listing: https://mcp.tc/i/date-calculator
- Connect: use the server's own URL `https://mcp.onlinealarmkur.com/` (no sign-in); clients connect to it directly. The listing link is a page, not an MCP endpoint.
- Type: remote (Streamable HTTP)
- Auth: none
- Category: [Utilities](https://mcp.tc/c/utilities)
- Vendor: Online Alarm Kur
- Homepage: <https://mcp.onlinealarmkur.com/>
- Repository: <https://github.com/onlinealarmkur/date-calculator-mcp>

## About

A read-only Gregorian date calculator that uses the same logic as onlinealarmkur.com. It counts days between two dates, adds or subtracts years, months, weeks and days, and can exclude chosen weekdays and public holidays. It also lists public holidays, including observed dates, for a country and optional region. Results include the rules used and a share link to the website.

The server is hosted and uses Streamable HTTP at https://mcp.onlinealarmkur.com/. No sign-in or API key is needed. Rate limits apply, and holiday lookups share a daily budget that resets at 00:00 UTC.

## What it can do

- Count calendar or matching days between two dates
- Exclude weekends, chosen weekdays or public holidays
- Add or subtract years, months, weeks and days
- List public holidays with observed dates for up to 11 years
- Find supported countries, regions and year coverage
- Get share links that open the same calculation on the website

## Tools (4)

- `count_days`: Count calendar or matching days between two dates, optionally excluding weekdays and holidays. (read-only)
- `shift_date`: Add or subtract years, months, weeks and days with optional weekday and holiday exclusions. (read-only)
- `get_holidays`: List public holidays, including observed dates, for a country, optional region and up to 11 years. (read-only)
- `list_locations`: List supported country codes, regions and year coverage. (read-only)

## Example prompts

- "How many working days are there between 2 November and 24 December 2026 in Germany?"
- "What date is 90 days after 15 January 2027?"
- "List the public holidays in Turkey for 2027."
- "Which region codes does Spain support for holidays?"

## Install

### Claude Code

1. Run this in a terminal, in your project folder:

```bash
claude mcp add --transport http date-calculator https://mcp.onlinealarmkur.com/
```

2. Start Claude Code and type `/mcp`. **date-calculator** should show as connected.

Add `--scope user` to make it available in every project, not just this one.

### Claude Desktop

1. Open **Customize → Connectors**, click **+ Add**, then **Add custom connector**.

2. Name it **Date Calculator** and paste this URL:

```url
https://mcp.onlinealarmkur.com/
```

3. Click **Add**. Its tools appear in the chat’s tools menu.

Claude Desktop’s JSON config file only starts local servers. Remote servers go through Connectors, and connectors you add on claude.ai show up here too.

### claude.ai

1. Open the connector form on claude.ai. This button fills in the name and URL for you:

[Add to claude.ai](<https://claude.ai/customize/connectors?modal=add-custom-connector&connectorName=Date%20Calculator&connectorUrl=https%3A%2F%2Fmcp.onlinealarmkur.com%2F>) (opens connector settings)

2. Check that the URL reads `https://mcp.onlinealarmkur.com/` and click **Add**.

3. Turn it on in a chat from the tools menu.

Free plans allow one custom connector. On Team and Enterprise plans an owner adds it under **Organization settings → Connectors**.

### ChatGPT

1. On chatgpt.com, go to **Plugins**, select **+**, then **Add custom MCP server**.

2. Enter a name for the server.

3. Under **Connection**, paste `https://mcp.onlinealarmkur.com/` as the server URL, then for authentication choose **No authentication**.

4. Check **I understand and want to continue**, then select **Create as a plugin**.

Whether you can add a custom MCP server depends on your ChatGPT plan and your workspace permissions (in Business workspaces, admins and owners can).

### Cursor

[Add to Cursor](<https://cursor.com/install-mcp?name=date-calculator&config=eyJ1cmwiOiJodHRwczovL21jcC5vbmxpbmVhbGFybWt1ci5jb20vIn0%3D>) (opens Cursor)

Or add it by hand to `~/.cursor/mcp.json` (all projects) or `.cursor/mcp.json` (this project):

`mcp.json`:

```json
{
  "mcpServers": {
    "date-calculator": {
      "url": "https://mcp.onlinealarmkur.com/"
    }
  }
}
```

### VS Code

[Install in VS Code](<https://vscode.dev/redirect/mcp/install?name=date-calculator&config=%7B%22type%22%3A%22http%22%2C%22url%22%3A%22https%3A%2F%2Fmcp.onlinealarmkur.com%2F%22%7D>) (opens VS Code)

Or from a terminal:

```bash
code --add-mcp '{"name":"date-calculator","type":"http","url":"https://mcp.onlinealarmkur.com/"}'
```

Or commit it to the repo in `.vscode/mcp.json`:

`.vscode/mcp.json`:

```json
{
  "servers": {
    "date-calculator": {
      "type": "http",
      "url": "https://mcp.onlinealarmkur.com/"
    }
  }
}
```

### Devin Desktop

1. Add it to `~/.config/devin/mcp_config.json` (macOS and Linux) or `%APPDATA%\devin\mcp_config.json` (Windows):

`mcp_config.json`:

```json
{
  "mcpServers": {
    "date-calculator": {
      "serverUrl": "https://mcp.onlinealarmkur.com/"
    }
  }
}
```

2. Refresh the MCP server list in Cascade.

Devin Desktop is the new name for Windsurf. It reads `serverUrl` (or `url`) for remote servers.

### Codex

```bash
codex mcp add date-calculator --url https://mcp.onlinealarmkur.com/
```

Or edit `~/.codex/config.toml` directly:

`config.toml`:

```toml
[mcp_servers.date-calculator]
url = "https://mcp.onlinealarmkur.com/"
```

### Gemini CLI

```bash
gemini mcp add --transport http date-calculator https://mcp.onlinealarmkur.com/
```

This adds it to the current project. Add `-s user` to use it everywhere.

### Any client

Most clients accept this shape. Some name the URL field differently: `serverUrl` in Devin Desktop, `httpUrl` in Gemini CLI’s settings file.

```json
{
  "mcpServers": {
    "date-calculator": {
      "type": "http",
      "url": "https://mcp.onlinealarmkur.com/"
    }
  }
}
```

Zed puts servers under `context_servers` in its settings. Cline needs `"type": "streamableHttp"`, or it assumes SSE.

Client only starts local servers? Bridge it with `npx -y mcp-remote https://mcp.onlinealarmkur.com/`.

## Recent changes

- 2026-11-04 14:51 UTC: New version 0.2.0 (was 0.1.0), reported by the server. Source: automatic check.
- 2026-11-04 14:51 UTC: 4 tools changed. Server instructions changed. Source: automatic check. Worth a look: new server instructions. Changed: count\_days, get\_holidays, list\_locations, shift\_date.
- 2026-11-03 23:22 UTC: Tracking started: 4 tools read. Source: automatic check.

More on the History tab, with descriptions before and after for the newest entries: https://mcp.tc/i/date-calculator#history (Atom feed: https://mcp.tc/i/date-calculator/history.xml). It records what mcp.tc's anonymous checks saw, every 3 hours where the tool list can be read without sign-in; it is not a security review.

## Details

- Server version: 0.2.0
- MCP protocol version: 2026-07-28
- Last checked: 2026-11-07 (reachable)
- Listed: 2026-11-03
- Updated: 2026-11-04

---
Source: https://mcp.tc/i/date-calculator (mcp.tc is an independent directory, not affiliated with this server's publisher). Corrections: https://mcp.tc/report