Happytails.aiFree tools. No account needed.
Find a tool

Date difference | agent view

The same page content and links, with explicit tool capabilities. Tools marked with an API can run directly through HTTP. Other tools require the browser interface or are not connected yet.

Tool capabilities

{
  "id": "date-difference",
  "category": "date-time-tools",
  "built": true,
  "requirements": "Inclusive/exclusive counting, leap years, calendar dates versus elapsed time.",
  "implementation": {
    "fields": [
      {
        "key": "start",
        "label": "Start date",
        "value": "2026-01-01",
        "type": "date"
      },
      {
        "key": "end",
        "label": "End date",
        "value": "2026-12-31",
        "type": "date"
      },
      {
        "key": "holidays",
        "label": "Holidays to exclude (YYYY-MM-DD, comma separated)",
        "value": "",
        "type": "text"
      }
    ],
    "input": false,
    "experience": {
      "automatic": true,
      "single": false,
      "label": "Your text",
      "placeholder": "Hello world!",
      "help": "Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.",
      "action": null
    },
    "mode": "automatic",
    "interactive": false
  },
  "execution": "POST /api/v1/tools/date-difference/run",
  "api": {
    "id": "date-difference",
    "name": "Date difference",
    "category": "date-time-tools",
    "description": "Inclusive/exclusive counting, leap years, calendar dates versus elapsed time.",
    "notes": "",
    "human_path": "/en/date-time-tools/date-difference/",
    "method": "POST",
    "endpoint": "/api/v1/tools/date-difference/run",
    "schema_url": "/api/v1/tools/date-difference",
    "input_schema": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "input": {
          "type": "string",
          "maxLength": 1000000,
          "default": "",
          "description": "Plain text input. File tools use files instead unless otherwise documented."
        },
        "options": {
          "type": "object",
          "additionalProperties": false,
          "properties": {
            "start": {
              "type": "string",
              "description": "Start date",
              "default": "2026-01-01"
            },
            "end": {
              "type": "string",
              "description": "End date",
              "default": "2026-12-31"
            },
            "holidays": {
              "type": "string",
              "description": "Holidays to exclude (YYYY-MM-DD, comma separated)",
              "default": ""
            }
          }
        }
      }
    },
    "output_schema": {
      "type": "object",
      "required": [
        "tool",
        "result"
      ],
      "properties": {
        "tool": {
          "type": "string"
        },
        "result": {
          "type": "object",
          "required": [
            "text",
            "files"
          ],
          "properties": {
            "text": {
              "type": [
                "string",
                "null"
              ]
            },
            "data": {
              "description": "Parsed JSON when the textual result is JSON."
            },
            "name": {
              "type": "string"
            },
            "mime": {
              "type": "string"
            },
            "files": {
              "type": "array",
              "items": {
                "type": "object",
                "required": [
                  "name",
                  "mime",
                  "bytes",
                  "base64"
                ],
                "properties": {
                  "name": {
                    "type": "string"
                  },
                  "mime": {
                    "type": "string"
                  },
                  "bytes": {
                    "type": "integer"
                  },
                  "base64": {
                    "type": "string",
                    "contentEncoding": "base64"
                  }
                }
              }
            }
          }
        }
      }
    },
    "processing": "Server; same transformation code as browser tools",
    "limits": {
      "request_bytes": 8388608,
      "input_characters": 1000000,
      "files_bytes": 5242880,
      "max_files": 0,
      "timeout_seconds": 12
    }
  },
  "agent_processing": "Server; same transformation code as browser tools",
  "browser_agent": {
    "supported": true,
    "name": "run_current_tool",
    "discovery": "WebMCP on the human page in a supporting browser",
    "verification": "See audit/API-AUDIT.md; availability is not verification"
  }
}

Page guide

Inclusive/exclusive counting, leap years, calendar dates versus elapsed time..

Useful next steps

Add days

Add/subtract calendar days and expose timezone/calendar assumptions.

Business days

Custom weekends first.

Time duration

Start/end times, crossing midnight, breaks, decimal hours and explicit timezone handling.

How to use Date difference

  1. Enter the values you want to calculate and choose the relevant units or settings.
  2. The result updates as you type. Adjust the available settings if needed.
  3. Review the result, then use Copy result or a download link when available.

Working with date difference

Date calculations can depend on calendar rules, time zones and whether endpoints are included. A duration in hours is different from a number of calendar days when daylight-saving changes occur.

Common questions

Are all days exactly 24 hours long?

Elapsed time across a daylight-saving transition can differ from a simple calendar-day count. Use the measure relevant to your schedule.

Why can the same timestamp show different dates?

A timestamp represents an instant, while a calendar date is interpreted in a time zone. Near midnight, the same instant can fall on different local dates.

Continue your workflow: Add days, Business days, Time duration.