Pregnancy due date calculator — track weeks, trimester, baby development by week.
- Runs locally
- Category Calculator
- Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.
What this tool does
Free online pregnancy due date calculator. Choose your method — last menstrual period (LMP, +280 days by Naegele's rule), known conception date (+266 days), or a recent ultrasound (date + reported gestational age) — and instantly see your estimated due date, current gestational age in weeks and days, trimester, baby's Chinese zodiac for the due- date year, and a short, factual fetal-development summary for every one of the 40 weeks (paraphrased from public ACOG and WHO guidance). Days and weeks until due update in real time, and the tool honors post-term arithmetic if your due date has passed. All calculation runs locally in your browser — the date you enter is never uploaded, never logged, never sent anywhere. This is an educational reference; it does not replace prenatal care or ultrasound dating by your obstetrician, which is more accurate than any formula.
Tool details
- Input
- Files + Numbers
- The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
- Output
- Live result
- The result area focuses on usable output, with copy, download, or preview actions when supported.
- Privacy
- Browser-side processing
- The main tool logic does not call an external API, so inputs normally stay in the current tab.
- Save / share
- No account required
- Open the page and use it; whether results survive refresh depends on the tool.
- Performance budget
- Initial JS <= 18 KB
- No WASM budget is declared, keeping the tool quick to open on mobile.
- Best fit
- Calculator · Content Creator
- Category and role tags drive related tools, internal links, and quick fit checks.
How to use
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1. Input
Paste or drop your content into the tool panel.
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2. Process
Click the button. All processing is local in your browser.
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3. Copy / Download
Copy the result or download to disk in one click.
How Pregnancy Due Date Calculator fits into your work
Use it for fast estimates, comparisons, and planning numbers before you make the final call.
Calculation jobs
- Getting a realistic range before a purchase, plan, workout, or schedule decision.
- Comparing scenarios by changing one input at a time.
- Turning rough assumptions into a number you can discuss.
Calculation checks
- Double-check units, dates, rates, and rounding assumptions.
- Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
- Save the inputs that produced an important result so you can reproduce it later.
Good next steps
These links move the current task into a more complete workflow.
- 1 Age Calculator Calculate your exact age — years, months, days, hours. Compare two dates or count to a future date. Open
- 2 Date Difference Calculator Days / weeks / months / years between two dates — plus business-days mode — browser-only Open
- 3 Lunar Calendar Converter (Chinese Nongli) Gregorian ⇄ Chinese Lunar (Nongli) calendar — bi-directional, accurate 1900-2100. Open
FAQ
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