Pregnancy Calculators

You’ve got the positive test, maybe even the first ultrasound photo saved on your phone. Now come the questions—how far along am I? Is this cramping normal? When should I go to the hospital? With so much changing week to week, keeping up can feel like its own job. That’s where pregnancy calculators come in.

These tools don’t replace checkups, but they help you stay informed and aware of what’s happening. Whether you’re checking your baby’s size at 18 weeks or trying to time contractions at 3 a.m., they make it easier to track the details. Most are quick to use, built for mobile or desktop, and tailored to match your unique dates and stats.

Here’s a breakdown of the most-used pregnancy calculators, what they do, and how to make the most of each one.

1. Due Date Calculator

Find your timeline

This one’s a classic for a reason. Enter the date of your last menstrual period (LMP), and it gives you an estimated due date. You can also adjust it using your cycle length or ultrasound measurements if available.

Why it matters:
Your due date helps schedule appointments, track milestones, and prepare for labor.

How to use it:
- Input your LMP
- Choose your average cycle length
- If you’ve had a dating ultrasound, enter that for a more accurate result

Good to know:
Only about 5% of babies arrive exactly on their due date. It’s a guide, not a deadline.

Tip:
Bookmark the result or add it to your calendar. Many tools also give trimester start dates.

2. Trimester & Week-by-Week Progress Tracker

See what’s happening each week

Pregnancy can feel like it moves both fast and slow. This tracker shows fetal growth, symptoms to expect, and common tests or appointments based on how far along you are.

What it does:
- Breaks pregnancy into weeks and trimesters
- Offers updates on baby’s development
- Lists common maternal symptoms and care tips

How to use it:
- Enter your due date or LMP
- Scroll through each week to see updates

Helpful features:
Some trackers include visual size comparisons (like "your baby is the size of a lemon") or checklists.

If it feels overwhelming:
Stick to current-week updates. Too much ahead of time can create unnecessary worry.

3. Contraction Timer

Know when it’s go time

As labor nears, contractions may start and stop for days. This timer helps you measure how long they last and how close together they are. Patterns are key.

What it tracks:
- Start and end time of each contraction
- Length and interval between them
- History log for comparison

When to use it:
- Once contractions feel regular or start picking up in strength
- If your doctor or midwife has asked you to keep track

How to read results:
- Early labor: contractions are far apart and irregular
- Active labor: closer together (usually 3 to 5 minutes apart), lasting 45–60 seconds

Smart practice:
Try timing a few test contractions before labor starts, so you know how the tool works.

4. Kick Count Tracker

Keep tabs on movement

Fetal movement is a sign of well-being. This tool helps you log how long it takes to feel a set number of kicks—usually 10 movements.

How it works:
- Choose a time when the baby is usually active
- Start the timer and count kicks
- Stop once you reach 10

When to use it:
Often recommended starting in the third trimester, or earlier if your provider suggests.

Tips for best results:
- Do it around the same time daily
- Sit or lie down in a quiet space
- If fewer movements are felt, try again after eating or drinking something cold

What to do if movement seems low:
Reach out to your provider. A noticeable drop in activity may need attention.

5. Pregnancy Weight Gain Tracker

Stay in the recommended range

This calculator compares your weight gain to general guidelines based on your starting weight and trimester. It helps you see if you’re tracking within the expected range.

How to use it:
- Enter your pre-pregnancy weight and height
- Log weight gain as it happens
- View how it compares to targets

Why it helps:
Weight gain affects energy, baby’s growth, and delivery outcomes. Too much or too little can be flagged early with consistent tracking.

Tips:
- Weigh yourself once a week under the same conditions
- Share patterns with your provider if anything seems off

If the numbers worry you:
Remember it’s not about perfection. Use this as a general guide, not something to stress over daily.

Sometimes the simplest tool makes a big difference. Let’s say you’re 33 weeks, trying to remember if the baby has moved much today. You open your kick counter, hit start, and within 20 minutes, you’ve logged 10 solid movements. That kind of peace of mind is what these tools are for.

You do not need to use all of them every day. Pick what fits your stage and what helps you stay informed without adding more pressure. Most tools are designed to be quick, clear, and easy to revisit whenever you need a refresher.