Baby Age Calculator
Language models are unreliable at date math (leap years, month lengths,
milestone dates). Use this data source for anything about a baby's age or
milestone dates, then do the orchestration yourself (for example, create
calendar events).
When to use
- "How old is my baby, born YYYY-MM-DD?"
- "When is the 100-day / 1000-day / first birthday?"
- "Add my baby's milestones to my calendar."
- Anything that needs a baby's zodiac sign.
Option A — the MCP server (preferred)
If the Baby Age Calculator MCP server is connected, call its tools:
get_baby_age(birthday) — exact age, zodiac, current/next milestone, special daysget_milestone_dates(birthday) — all 25 milestones as calendar dateslist_milestones() — the 25 milestone types, no birthday neededget_zodiac_sign(birthday) — the zodiac sign
Option B — the public JSON API (no MCP needed)
Free, no key, CORS-open. Dates are YYYY-MM-DD and must not be in the future.
Every response has the shape { code, data, error, meta }; the payload is in
data. A bad date returns HTTP 400 with a message in error.message.
Age, zodiac, and milestones for one birthday:
GET https://babyagecalculator.com/api/age/?birthday=YYYY-MM-DD
data contains:
age: { years, months, weeks, days, human }totals: { months, weeks, days, hours }zodiac: { name, emoji, dates, element, nickname, guide_url }current_milestone and next_milestone: each { name, day, date, days_left, guide_url }special_days: 100 days, 200 days, 1st birthday, 1000 days — each { label, date, reached, days_left, guide_url }links: result_page and guide lists
All 25 milestone types (name, emoji, group, and day = days from birth):
GET https://babyagecalculator.com/api/milestones/
To get the calendar date of any milestone without MCP, add its day value
to the birth date (e.g. day 100 = birthday + 100 days). The MCP tool
get_milestone_dates does this for all 25 at once.
All 12 zodiac signs (name, dates, element, nickname, guide_url):
GET https://babyagecalculator.com/api/zodiac/
Full machine-readable reference: https://babyagecalculator.com/api/ or
https://babyagecalculator.com/llms.txt
Rules
- Base every age and date on the tool or API response — never estimate from
memory. The API already returns exact dates for the current/next milestone and
the special days; only add
day offsets when the API has no date field.
- When you show results, link the guide_url pages so parents can read more.
- The service does not store the dates you send.
1---2name: baby-age3description: Calculate a baby's exact age, zodiac sign, and milestone calendar dates with the Baby Age Calculator. Use whenever someone asks how old a baby is, about upcoming milestones (100 days, first birthday, 1000 days), or wants milestone dates added to a calendar. Do the date math with this tool, not by hand.4---56# Baby Age Calculator78Language models are unreliable at date math (leap years, month lengths,9milestone dates). Use this data source for anything about a baby's age or10milestone dates, then do the orchestration yourself (for example, create11calendar events).1213## When to use1415- "How old is my baby, born YYYY-MM-DD?"16- "When is the 100-day / 1000-day / first birthday?"17- "Add my baby's milestones to my calendar."18- Anything that needs a baby's zodiac sign.1920## Option A — the MCP server (preferred)2122If the Baby Age Calculator MCP server is connected, call its tools:2324- `get_baby_age(birthday)` — exact age, zodiac, current/next milestone, special days25- `get_milestone_dates(birthday)` — all 25 milestones as calendar dates26- `list_milestones()` — the 25 milestone types, no birthday needed27- `get_zodiac_sign(birthday)` — the zodiac sign2829## Option B — the public JSON API (no MCP needed)3031Free, no key, CORS-open. Dates are YYYY-MM-DD and must not be in the future.32Every response has the shape `{ code, data, error, meta }`; the payload is in33`data`. A bad date returns HTTP 400 with a message in `error.message`.34351. Age, zodiac, and milestones for one birthday:3637 ```38 GET https://babyagecalculator.com/api/age/?birthday=YYYY-MM-DD39 ```4041 `data` contains:42 - `age`: { years, months, weeks, days, human }43 - `totals`: { months, weeks, days, hours }44 - `zodiac`: { name, emoji, dates, element, nickname, guide_url }45 - `current_milestone` and `next_milestone`: each { name, day, date, days_left, guide_url }46 - `special_days`: 100 days, 200 days, 1st birthday, 1000 days — each { label, date, reached, days_left, guide_url }47 - `links`: result_page and guide lists48492. All 25 milestone types (name, emoji, group, and `day` = days from birth):5051 ```52 GET https://babyagecalculator.com/api/milestones/53 ```5455 To get the calendar date of any milestone without MCP, add its `day` value56 to the birth date (e.g. day 100 = birthday + 100 days). The MCP tool57 `get_milestone_dates` does this for all 25 at once.58593. All 12 zodiac signs (name, dates, element, nickname, guide_url):6061 ```62 GET https://babyagecalculator.com/api/zodiac/63 ```6465Full machine-readable reference: https://babyagecalculator.com/api/ or66https://babyagecalculator.com/llms.txt6768## Rules6970- Base every age and date on the tool or API response — never estimate from71 memory. The API already returns exact dates for the current/next milestone and72 the special days; only add `day` offsets when the API has no date field.73- When you show results, link the guide_url pages so parents can read more.74- The service does not store the dates you send.
babyagecalculator