Pregnancy Calculator
See how far along you are and your estimated due date from your last menstrual period (LMP) and cycle length — with current week, trimester, days remaining, and estimated conception date.
How to Use
- Enter the first day of your last menstrual period (LMP) using the date picker.
- Adjust the cycle length if yours is not the typical 28 days — longer cycles push the due date later.
- Read how far along you are in weeks and days, and your estimated due date.
- Check which trimester you are in and how many days remain until the due date.
- Use the quick presets to model a pregnancy at 6, 12, 20, or 30 weeks along.
Show Work
Notes
About the Pregnancy Calculator
The Pregnancy Calculator gives you a fast, free answer for health and fitness tracking without sending anything off your device. See how far along you are and your estimated due date from your last menstrual period (LMP) and cycle length — with current week, trimester, days remaining, and estimated conception date.
How it works
Enter your figures and the result appears instantly, updating the moment you change anything. There is no submit button and nothing to wait for, so it is easy to try a few what-if numbers and compare the results. Just check each box holds the kind of value it expects.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
How is "how far along" calculated?
Gestational age is counted from the first day of your last menstrual period (LMP), not from conception. It is the number of days between today and your LMP, expressed as completed weeks plus days — for example "14 weeks 3 days." Because dating starts at LMP, you are counted as about 2 weeks pregnant at the moment of conception.
How is the due date estimated?
This uses Naegele's rule, adjusted for cycle length: due date = LMP + 280 days (40 weeks), shifted by however many days your cycle differs from 28. A 32-day cycle, for instance, moves the due date 4 days later because ovulation happens later. Only a small fraction of babies arrive on the exact estimated date; most come within two weeks either side.
What are the three trimesters?
<strong>First trimester:</strong> up to 13 weeks 6 days. <strong>Second trimester:</strong> 14 weeks 0 days to 27 weeks 6 days. <strong>Third trimester:</strong> 28 weeks onward to delivery. The calculator labels your current trimester from your gestational age. Boundaries vary slightly between sources, but the 14- and 28-week marks are standard.
My cycle is irregular — is this still useful?
LMP-based dating assumes reasonably regular cycles with ovulation near the midpoint. If your cycles are irregular or you are unsure of your LMP, the estimate can be off by a week or more. A first-trimester ultrasound dates the pregnancy far more reliably and is what your provider will rely on.
Is this medical advice?
No. This calculator is for general information and planning only and is not medical advice. Pregnancy dating, milestones, and any health concerns should be confirmed with a qualified healthcare provider, who will use ultrasound and clinical exams for the official assessment.
How do I use the Pregnancy Calculator?
Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.
Does it cost anything or need an account?
No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.
Is anything I type uploaded?
No. The tool works entirely on your device, so the values you enter never leave your browser.
Common Use Cases
Knowing your current week
See exactly how far along you are so you can follow week-by-week pregnancy guides and apps.
Estimating the due date
Get a quick LMP-based due date to plan around before your first prenatal appointment.
Planning maternity leave
Use the due date and days remaining to schedule the start of leave and work coverage.
Tracking the trimester
Know which trimester you are in to anticipate scans, screenings, and milestones.
Counting down
Watch the days-remaining figure to prepare the nursery, hospital bag, and logistics.
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