Calculate your BMI and weight-loss estimate
Enter your current details. The calculator estimates BMI, a height-based reference range, calories, and a timeline for your chosen goal.
Example data table
These examples show how height and weight combine to create a BMI. They are illustrations, not personal recommendations.
| Height | Weight | BMI | Height-based healthy BMI reference | General category |
|---|---|---|---|---|
| 155 cm | 60 kg | 25.0 | 44.4–59.8 kg | Overweight range |
| 160 cm | 65 kg | 25.4 | 47.4–63.7 kg | Overweight range |
| 165 cm | 70 kg | 25.7 | 50.4–67.8 kg | Overweight range |
| 170 cm | 75 kg | 26.0 | 53.5–72.0 kg | Overweight range |
Formula used
The calculator uses the standard BMI equation for adults. It also uses a female resting-energy estimate and activity multipliers for planning.
The time estimate divides weight to lose by the estimated weekly loss. Bodies do not lose weight in a perfectly straight line.
How to use this calculator
- Choose metric or imperial measurements.
- Enter your age, height, current weight, and target weight.
- Select the activity level that matches your usual week.
- Select a weekly loss pace that feels realistic.
- Choose Calculate results to view your estimate above the form.
- Review the notices before using any calorie target.
- Use the CSV button for a spreadsheet record.
- Use Download Result PDF, then select Save as PDF.
BMI and sustainable weight-loss planning
What BMI shows
Body mass index compares body weight with height. The number cannot measure body fat directly. It also cannot show where body fat is stored. A repeated result may reveal a direction over time. Use it beside your health history and daily habits. Never treat one number as your complete health story.
Why women need context
Women can have different body compositions at the same BMI. Hormones, life stage, muscle mass, and genetics matter. Menstrual cycles can change scale weight temporarily. Pregnancy and breastfeeding need separate nutrition guidance. Menopause can also change body composition and energy needs. A BMI category does not diagnose a medical condition. It simply supports a broader conversation about health. Personal care matters more than a universal target.
Understanding your calorie estimate
The calculator estimates resting energy with the Mifflin–St Jeor equation. Resting energy supports breathing, circulation, and basic body functions. An activity factor then estimates daily energy use. This estimate is called total daily energy expenditure. Real needs can differ from the displayed value. Sleep, stress, medication, illness, and training can affect results. Use the calorie target as a starting estimate. Review your progress after several consistent weeks.
Choosing a weight goal
A target weight should feel realistic and personally meaningful. The healthy BMI range provides a height-based reference. It is not a requirement for every person. Choose smaller milestones when the full goal feels distant. A five kilogram change can still improve daily comfort. Focus on behaviors that you can repeat. Reassess the target as your body and lifestyle change.
Pick a sustainable pace
Fast plans can be difficult to maintain. A moderate calorie deficit often supports steadier progress. This calculator converts your selected pace into a daily deficit. The displayed weeks are an estimate, not a deadline. Weight can change unevenly from water and digestion. Strength training can add muscle while fat decreases. Review trends instead of single weigh-ins. Adjust slowly when your plan feels exhausting or restrictive.
Track more than the scale
The scale is one useful measurement. Add waist measurements, energy, strength, sleep, and mood. Notice whether everyday movement feels easier. Record meals only when tracking feels helpful. Avoid using numbers as punishment. A weekly average can reduce anxiety from normal changes. Photos and clothing fit can provide extra context. Celebrate routines that improve your confidence and wellbeing.
Build supportive habits
Start with meals that include protein, fiber, and satisfying foods. Keep convenient options available at home. Plan movement that you genuinely enjoy. Walking, cycling, and resistance training all count. Aim for regular sleep whenever possible. Drink enough fluids throughout the day. Make one small change before adding another. Consistency becomes easier when your plan fits normal life.
When personal advice matters
Speak with a qualified clinician before dieting during pregnancy or breastfeeding. Get individualized advice for eating disorders, diabetes, thyroid disease, or kidney disease. Ask for help if fatigue, dizziness, or missed periods occur. A registered dietitian can tailor targets to your needs. Use this calculator for education, not diagnosis. Respect your body while building lasting health habits.
Frequently asked questions
1. What does BMI measure?
BMI compares weight with height. It is a screening measure for adults. It does not measure body fat, fitness, or health on its own. Use it with other information, such as waist size, medical history, habits, and professional advice.
2. Is this calculator only for women?
The BMI equation is the same for adult women and men. This page uses the female Mifflin–St Jeor resting-energy equation for calorie estimates. It is designed for adult women planning gradual weight loss.
3. Why does the calculator ask for age?
Age is used in the resting-energy estimate. Energy needs often change with age, body composition, activity, and health. The result remains an estimate, not a clinical measurement of your metabolism.
4. Which activity level should I choose?
Choose the option that fits your usual week, not your best week. Include work movement, exercise, and regular walking. When uncertain, choose the lower level and review results after several weeks.
5. Why can my scale weight change quickly?
Water, sodium, digestion, hormones, and glycogen can shift scale weight daily. Compare weekly averages or measurements taken under similar conditions. A short-term increase does not automatically mean fat gain.
6. Is the calorie target a medical prescription?
No. It is an educational estimate from equations and selected activity. Personal needs can differ. Speak with a registered dietitian or clinician when you need individualized nutrition, illness management, or medication guidance.
7. What happens if my target is below the reference range?
The calculator displays a notice. A BMI reference range is only one screening tool, yet a low target can require individual assessment. Discuss a safe target with a qualified clinician before continuing.
8. Can I use the calculator during pregnancy?
No weight-loss target should be set from this tool during pregnancy. Pregnancy needs individualized guidance. Use prenatal care advice instead, and discuss weight changes with your obstetric clinician or midwife.
9. Can I use it while breastfeeding?
Breastfeeding changes energy needs and nutrition priorities. A general calorie estimate may not fit you. Speak with a clinician or dietitian before setting a deficit or rapid timeline.
10. Why is there a 1,200 calorie floor?
The display avoids showing an even lower general target. It is not a universal minimum or a personalised recommendation. If your estimate reaches that floor, obtain professional advice before restricting intake further.
11. How often should I recalculate?
Recalculate after a meaningful change in weight, activity, routine, or goal. Every four to six weeks is often enough for planning. Avoid changing targets daily because normal fluctuations can be misleading.
BMI is a screening measure, not a diagnosis. Consult a qualified health professional for personalized advice, especially with medical conditions, pregnancy, breastfeeding, or a history of disordered eating.