Online Due Date Calculator
Due Date Calculator estimates your due date and current pregnancy week from your last period, ultrasound, conception date, or IVF transfer — with a milestone calendar.
| RESULT | |
|---|---|
| Your checking esults will appear here... | You probably are not pregnant yet. |
| The estimated due date | -- |
| Current Pregnancy Stage (Week number) | -- |
| Trimester | -- |
| Baby size and weight | -- On average, your baby weight less than 1 gram at this stage. |
| Your baby was likely conceived on | -- |
| PREGNANCY WEEK CALENDAR | |||
|---|---|---|---|
| Date | Trimester | Important Milestones | |
| 1 | -- | 1 | |
| 2 | -- | 1 | Baby conceived |
| 3 | -- | 1 | Pregnancy test positive |
| 4 | -- | 1 | Heartbeat detectable by ultrasound |
| 5 | -- | 2 | Miscarriage risk decreases |
| 6 | -- | 2 | Baby begins making noticeable movements, can hear sounds, and gender can be found out. |
| 7 | -- | 2 | Premature baby may survive |
| 8 | -- | 3 | Baby can breathe |
What Is This Tool?
The Due Date Calculator estimates your due date and shows how far along you are right now. You can base the estimate on four starting points: the first day of your last period (with cycle length), an ultrasound dating, your conception date, or an IVF transfer date and embryo age. From there it works out your estimated due date, your current week and trimester, your baby's typical size and weight for that week, your likely conception date, and a week-by-week milestone calendar. If the dates fall outside the expected range, it lets you know rather than showing a result. The result can be downloaded as a PDF.
How to Use This Tool?
- Choose what to base the estimate on.
- Enter the relevant date, plus cycle length, ultrasound dating, or embryo age as needed.
- Click Calculate to see your due date and current stage.
- Review the milestone calendar and download a PDF if you'd like.
Key Features
- Estimates your due date from four starting points: last period, ultrasound, conception date, or IVF transfer.
- Shows how far along you are now — current week and trimester.
- Displays your baby's estimated size and weight for the current week.
- Estimates your likely conception date.
- Provides a week-by-week milestone calendar and a PDF download.
Examples
- Based on a last-period date with a 28-day cycle, the start date is the period date itself.
- A conception date sets the pregnancy start about two weeks earlier.
- A day-5 IVF transfer counts back 19 days to the gestational start.
- At 19 weeks, the tool shows a baby around 8.74 inches and 7.87 ounces.
Common Use Cases
- Finding your estimated due date early in pregnancy.
- Checking which week and trimester you're currently in.
- Following your baby's growth week by week.
- Estimating when conception likely occurred.
- Planning around key pregnancy milestones.
Tips & Best Practices
- Use the dating method your provider considers most reliable.
- For ultrasound dating, enter the weeks and days measured at the scan.
- Pick the correct embryo age for an IVF transfer.
- Re-check as you get updated dating from appointments.
- Treat the due date as an estimate — few babies arrive exactly on it.
Limitations
- Due dates are estimates; only about 1 in 20 babies arrive on the exact date.
- Accuracy depends on the dates and cycle information you enter.
- It isn't medical advice — your provider's dating takes precedence.
- Nothing is saved between sessions — only the current result can be exported as a PDF.
Frequently Asked Questions
- How is the due date calculated?
- It estimates the pregnancy start date from your chosen input, then projects roughly 280 days to the due date.
- What if it says "not yet"?
- The dates entered place you outside the expected range, so check them — or that conception has actually occurred.
- Why does it ask for cycle length?
- With a last-period date, cycle length adjusts the estimated start for shorter or longer cycles.
- Is the baby size exact?
- No, it's a typical average for the week and varies from baby to baby.
Key Terminology
- Estimated due date
- The projected birth date, about 280 days from the gestational start.
- Gestational age
- How far along the pregnancy is, counted from the start date.
- Trimester
- One of the three stages of pregnancy.
- Last menstrual period (LMP)
- The first day of your last period, a common dating reference.
- Embryo age
- The number of days an IVF embryo developed before transfer.