Based on standard reference ranges, your pre-pregnancy BMI is in the 18.5–24.9 (Healthy weight range). These ranges are based on IOM 2009 guidelines — your provider may set a personalised target.
How to use this calculator
Choose your measurement system (imperial or metric), enter your pre-pregnancy weight and height, and select whether you are expecting a single baby or twins. You can also enter your current gestational week to see a reference cumulative gain range for how far along you are. The calculator shows your pre-pregnancy BMI and the IOM 2009 recommended total and weekly gain ranges for your BMI category.
Understanding your result
The recommended gain ranges come from the Institute of Medicine's 2009 guidelines, which are the most widely referenced in clinical practice. They are based on population studies and designed to support healthy outcomes for most pregnancies — not as a strict target for every individual. Your pre-pregnancy BMI is shown as context only. It is never presented as a verdict. Weekly gain guidance is most relevant from the second trimester onwards; first trimester gain is typically minimal.
Disclaimer
Menstrual cycles, fertility, and pregnancy vary significantly between individuals. Results from this tool are statistical estimates and may not reflect your personal health. This is not medical advice, a diagnosis, or a substitute for professional care. If you have concerns about your pregnancy or reproductive health, consult a gynaecologist or healthcare provider.
Track this in OptiAI
Track your pregnancy week by week, log appointments, weight and scans, and see everything in one place with OptiAI.