Pregnancy Weight Gain Calculator

The calculator first uses your unrounded pre-pregnancy BMI to select a category and a published total range. Displayed BMI, weights, and derived ranges are rounded to one decimal place only after the BMI classification and range calculations.

The approximate end-weight range is your baseline weight plus the total guideline gain range. It is not an ideal, healthy, exact, or predicted delivery weight. A negative current change is valid input and is not a diagnosis.

For a singleton, current change is shown as arithmetic and published second- and third-trimester rates provide context. Pregnancy Metrics does not classify current change against a custom cumulative weekly band.

If you need to know how many completed weeks and days you are on a reference date, use the Pregnancy Timeline Calculator with the due date in your pregnancy record.

The calculator uses the unrounded BMI from the entered pre-pregnancy height and weight, then selects the published total range for the explicitly chosen pregnancy type. The result itself displays the exact range used and the baseline-plus-range arithmetic.

One-baby and twin references are separate. Published later-trimester rates remain context rather than a cumulative weekly formula, and the framework does not create a separate target for obesity at BMI 40 or above. Read the Pregnancy Weight Gain Guidelines for the full evidence tables, source provenance, and guideline history.

Current official sources publish total ranges, first-trimester assumptions, and second- and third-trimester rate context. CDC also provides BMI-specific weekly Pregnancy Weight Gain Trackers for week-by-week comparison.

Pregnancy Metrics does not reconstruct a CDC weekly band from a chart without authoritative numerical source data. If you want a week-by-week comparison, use the applicable CDC Pregnancy Weight Gain Tracker and discuss the result with your care team.

This tool does not classify first-trimester progress from a single weight. It also does not infer fetal weight, fluid status, viability, treatment need, or delivery timing.

Twins use their own BMI-specific published total range; the result shows the exact range selected. The underweight-twin value is treated as a CDC-published exception rather than recast as a National Academies recommendation.

Twins do not receive a fabricated week-specific target band in this tool. For triplets or more, this page calculates BMI and current change when supplied but does not present a standard numeric gain range or week-specific classification. Discuss individualized guidance with the care team.

• A single weight cannot assess pregnancy health or fetal wellbeing.
• The tool does not provide calories, diet, exercise, or weight-loss instructions.
• It does not diagnose gestational diabetes, preeclampsia, fluid changes, fetal-growth conditions, or any other condition.
• NAM uses adult BMI cutoffs; people under 18 may need individualized growth interpretation.
• Your prenatal care team may use information unavailable to this calculator and may give a different target or interpretation.

The checkbox records that your baseline is estimated; it does not create an uncertainty interval. Near a BMI cutoff, a different actual pre-pregnancy weight could place you in another category and change the guideline reference.

Height and weight are converted to canonical metric values for calculation. The supported calculator range is designed to catch obvious entry errors, not to define medical eligibility or diagnose a cycle or pregnancy. The optional tracker is off by default and uses localStorage only after you explicitly choose to keep it on this device.

Tracker values are not put in the URL, sent to a server API, or used for advertising audiences. See the Privacy Policy for the current data flow and the Medical Disclaimer for educational-use limits.

Each source below is linked to the specific type of statement it supports. These sources do not endorse Pregnancy Metrics.

1. ACOG — Weight Gain During Pregnancy

   Supports the BMI framework and singleton total ranges, provisional normal/overweight/obesity twin ranges, and individualized clinical judgment; it does not establish the underweight-twin exception.

2. ACOG patient guidance — How Much Weight Should I Gain During Pregnancy?

   Supports first-trimester variability and the contextual nature of pregnancy weight-gain guidance.

3. CDC — Weight Gain During Pregnancy

   Supports the current BMI-specific singleton and twin ranges, including the CDC-published 50–62 lb underweight-twin exception (shown here as 22.7–28.1 kg converted from that published range), official Pregnancy Weight Gain Trackers, and discussion with a provider for triplets or more.

4. National Academies — Weight Gain During Pregnancy: Reexamining the Guidelines

   Provides the 2009 BMI-based framework, the first-trimester 0.5–2.0 kg assumption, and published second- and third-trimester rate context; it does not provide a machine-readable cumulative weekly band for this page to reproduce.

5. NICE — Maternal and child nutrition

   Supports a non-stigmatizing boundary: this tool does not prescribe intentional pregnancy weight loss, diet, or treatment.