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Pregnancy Weight Gain Calculator

Check your pre-pregnancy BMI category, see the recommended total gain range, and compare your actual weight gain with week-by-week guidance for a single baby or twins.

Pre-pregnancy BMI

25.0

Normal

Recommended Total Gain

25 to 35 lb

IOM guideline range

Recommended So Far

10.8 to 16.9 lb

By week 24

Actual Gain So Far

18.0 lb

Over

Week-by-week tracking

Compare your progress with the recommended range at key milestones.

Above the recommended range
Week 12Recommended 1.0 to 4.1 lb
0 lb35 lb

Actual gain shown by the vertical marker: 18.0 lb.

Week 20Recommended 7.3 to 12.3 lb
0 lb35 lb

Actual gain shown by the vertical marker: 18.0 lb.

Week 28Recommended 14.4 to 21.4 lb
0 lb35 lb

Your actual marker appears once you reach week 28.

Week 36Recommended 21.5 to 30.5 lb
0 lb35 lb

Your actual marker appears once you reach week 36.

Week 40Recommended 25.0 to 35.0 lb
0 lb35 lb

Your actual marker appears once you reach week 40.

Consult your healthcare provider.

Editorial noteMaintained by EveryCalc - Reviewed June 2026

EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.

Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.

Learn more about our review process on the EveryCalc methodology page.

How this calculator works

What this page estimates

This Pregnancy Weight Gain Calculator is built to give a quick, browser-based estimate for pregnancy weight gain. Check your pre-pregnancy BMI category, see the recommended total gain range, and compare your actual weight gain with week-by-week guidance for a single baby or twins. The inputs stay on the page during normal use, and the result should be treated as an estimate for planning, comparison, or education rather than professional advice.

Calculation approach

The calculator applies the standard relationship implied by the inputs, then formats the answer so it can be checked and reused. For health tools, the most important step is using consistent units, rates, time periods, and assumptions before comparing the result with another calculator or outside quote.

Example workflow

For example, start with a realistic value you already know, change one input at a time, and watch how the answer moves. That makes it easier to tell whether the result is being driven by the main amount, the rate, the time period, or a unit conversion.

Practical checks

  • Use current, real-world numbers when the result affects money, health, tax, or legal decisions.
  • Run a low, base, and high case when the inputs are estimates.
  • Check the related calculators below when the next decision depends on a different assumption.

How to interpret the pregnancy weight gain result

Best use

Use the result as an informational wellness estimate that can help organize measurements, targets, or timing before a conversation with a clinician.

Cross-check

Compare the output with your own records, device readings, lab values, medication instructions, or guidance from a qualified health professional.

Watch for

Do not use this page to diagnose, treat, or ignore symptoms. Health calculators are most useful when they make questions clearer, not when they replace care.

This page belongs to the Health calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.

Before relying on this pregnancy weight gain estimate

Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.

Use current measurements

Recent weight, height, age, activity, nutrition, sleep, or timing inputs matter more than remembered estimates.

Look for context

A calculator can organize a wellness number, but it cannot read symptoms, medical history, medications, or lab results.

Escalate high-impact questions

Use clinical guidance for pregnancy, dosage, heart, risk, illness, or treatment decisions.

Rerun this page when measurements change, a clinician gives new guidance, or the result is being used for a new goal.

How to Use

  1. Enter your pre-pregnancy weight and your current weight in pounds or kilograms.
  2. Add your height so the calculator can estimate your pre-pregnancy BMI category.
  3. Choose your current pregnancy week and turn on the twins option if needed.
  4. Review your recommended total gain, suggested gain so far, and whether you are currently under, on track, or over the guideline range.

Frequently Asked Questions

How is recommended pregnancy weight gain determined?

The calculator uses Institute of Medicine guideline ranges based on your pre-pregnancy BMI category. Lower BMI categories generally have higher recommended weight gain ranges, while higher BMI categories have lower ranges.

Why does the calculator ask for height?

Your height is used with your pre-pregnancy weight to estimate your pre-pregnancy BMI. That BMI category helps determine the recommended total pregnancy weight gain range.

Are twin pregnancy recommendations different?

Yes. Twin pregnancies usually have higher recommended weight gain ranges than singleton pregnancies. This calculator applies a separate set of higher ranges when the twins option is enabled.

What if my weight gain is outside the recommended range?

A result outside the guideline range does not automatically mean something is wrong, but it is a good reason to check in with your healthcare provider. Individual needs can vary based on your medical history, symptoms, and pregnancy progress.

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