Pregnancy Calculator

Estimate your due date and current gestational age from your last period, conception date, IVF transfer, ultrasound, or known due date.

Pregnancy details

First day of your last period. Most common method.

Educational only. Most due dates come from a combination of LMP and an early ultrasound — confirm yours with your OB-GYN, midwife, or family physician.

What this pregnancy calculator does

This calculator tracks your pregnancy week by week, estimates your due date, and tells you what's happening as your baby grows. You enter the date of your last period or your conception date. It then maps out your pregnancy timeline and progress.

The due date is an estimate, not an exact appointment. Babies arrive on their own schedule, so think of it as a helpful target rather than a fixed deadline.

How is my due date calculated?

Your due date is usually calculated from the first day of your last period. The standard method adds 40 weeks to that date.

This is because pregnancy is traditionally counted from your last period, even though conception happens a couple of weeks later. If you know your conception date, the calculation adjusts for that. Your doctor may also refine the date using an early ultrasound, which can be more precise.

How accurate is a due date?

It's a useful estimate, not a guarantee. Only a small share of babies actually arrive on their exact due date.

In fact, only about 1 in 20 babies are born on their due date. Most arrive in the two weeks before or after. A full-term pregnancy is considered anywhere from 37 to 42 weeks, so there's a wide normal window. Try not to fixate on the single date.

How is pregnancy divided into trimesters?

Pregnancy is split into three trimesters, each with its own changes. Knowing them helps you understand what to expect.

The three trimesters are roughly:

  1. First trimester, weeks 1 to 12, when early development happens.
  2. Second trimester, weeks 13 to 26, often when energy returns.
  3. Third trimester, weeks 27 to birth, as your baby grows and prepares.

Each trimester brings different symptoms and milestones. The calculator helps you see where you are in this journey.

What happens week by week?

Your baby develops in remarkable ways each week. Following along can make the experience feel more real and connected.

Early on, major organs and structures begin forming. In the middle months, you may feel the first movements and learn the baby's size. Later, your baby gains weight and gets into position for birth. Weekly updates can help you feel informed and prepared at each stage.

Why does knowing my timeline help?

Your pregnancy timeline guides important care and planning. It's about more than just counting down.

Knowing how far along you are helps schedule prenatal checkups, screenings, and tests at the right times. It also helps you prepare practically and emotionally. And following your baby's growth can be a genuinely joyful part of the experience.

When should you see your doctor?

Regular prenatal care is one of the best things you can do for a healthy pregnancy. Your appointments are key checkpoints along the way.

See your doctor regularly throughout pregnancy, and reach out sooner if you have concerns like heavy bleeding, severe pain, or a noticeable drop in your baby's movements later on. You can read more about common symptoms in our guide on pregnancy symptoms and when to call your doctor. Never hesitate to ask about anything that worries you.

How can you support a healthy pregnancy?

A few steady habits support both you and your baby. None of them need to be complicated.

Helpful steps include:

  • Attending all your prenatal appointments.
  • Taking prenatal vitamins, especially folic acid.
  • Eating a balanced, varied diet.
  • Staying gently active, as your doctor advises.
  • Getting enough rest and managing stress.

Be kind to yourself through this time. Every pregnancy is different, and doing your best is enough.

Using your timeline to plan

Think of your pregnancy timeline as a map for an exciting journey. It helps you stay informed and prepared at each step.

As your due date approaches, the Pregnancy Weight Gain Calculator can help you track healthy weight gain along the way. Whatever stage you're at, following your progress can make this experience feel that much more special.

Questions about your pregnancy, due date, or what to expect?

august is a private AI health companion that can help you understand your pregnancy timeline, make sense of each stage, and figure out what to ask your doctor.

  • Private, no judgment
  • Available 24/7
  • Trained on health and wellbeing
Talk to august

Frequently Asked Questions

It's usually calculated from the first day of your last period, adding 40 weeks. Pregnancy is traditionally counted from your last period, even though conception happens a couple of weeks later. An early ultrasound can refine the date and may be more precise.

It's a useful estimate, not a guarantee. Only about 1 in 20 babies arrive on their exact due date, and most come in the two weeks before or after. A full-term pregnancy ranges from 37 to 42 weeks, so there's a wide normal window. Try not to fixate on one date.

The first trimester is weeks 1 to 12, when early development happens. The second is weeks 13 to 26, often when energy returns. The third is week 27 to birth, as your baby grows and gets into position. Each brings different symptoms and milestones.

It guides important care and planning. Knowing how far along you are helps schedule prenatal checkups, screenings, and tests at the right times. It also helps you prepare practically and emotionally, and following your baby's growth can be a joyful part of the experience.

See your doctor regularly, and reach out sooner for concerns like heavy bleeding, severe pain, or a noticeable drop in your baby's movements later on. Never hesitate to ask about anything that worries you. It's always okay to call.

Attend all your prenatal appointments, take prenatal vitamins including folic acid, eat a balanced diet, stay gently active as your doctor advises, and get enough rest. Be kind to yourself, since every pregnancy is different and doing your best is enough.