Overweight Calculator
Find out your BMI, how much you are over or under a healthy weight, and your ideal weight based on multiple methods.
| BMI Range | Category | Health Risk |
|---|---|---|
| < 18.5 | Underweight | Increased (malnutrition, osteoporosis) |
| 18.5 – 24.9 | Normal Weight | Minimal |
| 25.0 – 29.9 | Overweight | Increased |
| 30.0 – 34.9 | Obese Class I | High |
| 35.0 – 39.9 | Obese Class II | Very High |
| ≥ 40.0 | Obese Class III | Extremely High |
Calculate your BMI, see exactly how much weight separates you from the overweight threshold, and compare against your ideal weight using the Robinson formula.
How Overweight Calculator Works
BMI is calculated the standard way (weight ÷ height²) and classified into six categories from underweight through Obese Class III, following World Health Organization thresholds. "Excess weight" is calculated as the difference between your current weight and the weight that would put you exactly at a BMI of 25 (the overweight threshold) for your height — a positive number means you're above that threshold, a negative number means you're below it.
The Robinson (1983) ideal weight formula (52 kg + 1.9 kg per inch over 5 feet for men, 49 kg + 1.7 kg per inch over 5 feet for women) is shown alongside the wider healthy BMI weight range (18.5–24.9) as two different reference points — one a single "ideal" estimate, the other a broader realistic target range.
"Weight to lose for normal BMI" calculates specifically how much weight would need to come off to bring you down to the top edge of the healthy range (BMI 24.9), giving a concrete target figure if reducing BMI classification is a specific goal.
See It In Action
Who Uses Overweight Calculator and Why
- Seeing exactly how many pounds separate your current weight from the BMI-25 overweight threshold, as a more concrete number than an abstract BMI score.
- Comparing the Robinson ideal weight estimate against the broader healthy BMI weight range to understand the difference between a single "ideal" figure and a realistic target range.
- Getting a specific "weight to lose for normal BMI" figure to discuss as a starting goal with a healthcare provider or trainer.
- Tracking BMI category changes over time (for example, moving from Overweight toward the high end of Normal) using the six WHO-based categories.
Mistakes to Avoid
- Treating the Robinson ideal weight figure as the one "correct" target weight — the calculator itself frames it as one reference point alongside the wider 18.5–24.9 healthy BMI range, not a single number to chase.
- Using BMI category alone to judge body composition — a muscular person can register as Overweight or Obese by BMI without carrying excess fat, since the formula only uses height and weight.
- Confusing "excess weight vs BMI 25" with "weight to lose for normal BMI" — they answer different questions (distance from the overweight threshold vs. distance from the top of the healthy range) and aren't interchangeable.
Tips for Best Results
- Look at the healthy BMI weight range rather than fixating on the single Robinson estimate — most health guidance treats a range, not one ideal number, as the more realistic target.
- Use the "excess weight vs BMI 25" figure as a way to talk about progress in concrete pounds rather than BMI points alone, since it's often easier to track a specific weight number day to day.
Fixing Common Problems
My 'excess weight' shows as negative. — A negative figure means your current weight is below the weight that corresponds to a BMI of 25 for your height — in other words, you're at or under the overweight threshold, which is expected and not an error.
Terms Explained
Robinson formula: A 1983 formula (52 kg + 1.9 kg per inch over 5 ft for men; 49 kg + 1.7 kg per inch over 5 ft for women) that estimates a single reference "ideal" body weight from height.
BMI threshold: A specific BMI value (like 25 for overweight, or 18.5 for the bottom of the healthy range) used as a cutoff between WHO weight categories.