Free Online Ideal Weight Calculator
Determine your ideal body weight (IBW) using four scientifically established formulas—Robinson, Miller, Devine, and Hamwi. Our accurate free online ideal weight calculator supports both US Imperial units and UK/EU Metric units, with healthy weight ranges aligned with the World Health Organization (WHO), NHS standards, and CDC guidelines.
Your Ideal Weight Results
BMI-Based Healthy Weight Range
Based on a healthy BMI of 18.5–24.9 for your height: — kg
Free Online Ideal Weight Calculator – Estimate Your Healthy Body Weight
Determining your ideal body weight is an excellent way to baseline your health status and structure your nutritional targets. While modern medicine recognizes that a "perfect" weight does not exist—since muscle distribution, bone structure, and physical fitness play huge roles—calculating your Ideal Body Weight (IBW) provides a highly reliable target range for clinical and health evaluations.
This accurate free online ideal weight calculator implements all four major historical equations used in clinical science: the **Robinson, Miller, Devine, and Hamwi equations**. It fully supports both US Imperial units and UK/EU Metric units, allowing you to view estimated targets from each formula side-by-side, along with a standard WHO BMI-based healthy range, NHS standards, and CDC guidelines.
How Ideal Weight Formulas Work
Historically, ideal body weight equations were developed to estimate medical dosages (such as anesthesia and critical care drugs) because muscle tissue and fatty tissue metabolize drugs at different rates. All formulas establish a base weight for a height of 5 feet (60 inches) and add or subtract a set coefficient for every inch above or below that height.
The standard equations are formulated as follows:
Robinson Formula (1983)
Miller Formula (1983)
Devine Formula (1974)
Hamwi Formula (1964)
How to Determine Your Body Frame Size
Bone density and thickness significantly affect what represents a healthy weight. To adjust your ideal weight targets accurately, our calculator incorporates frame size adjustments. You can determine your frame size using the simple wrist test:
- Wrap your thumb and middle finger around the smallest part of your wrist.
- If your fingers overlap, you have a small frame (your ideal weight is adjusted by -10%).
- If your fingers just touch, you have a medium frame (no adjustment is applied).
- If your fingers do not touch, you have a large frame (your ideal weight is adjusted by +10%).
Ideal Weight Reference Table by Height
The table below indicates the ideal weight targets in kilograms and pounds for a medium frame (using the Robinson formula as a baseline):
| Height | Height (cm) | Male IBW (kg / lbs) | Female IBW (kg / lbs) |
|---|---|---|---|
| 5′ 0″ | 152.4 cm | 52.0 kg (115 lbs) | 49.0 kg (108 lbs) |
| 5′ 2″ | 157.5 cm | 55.8 kg (123 lbs) | 52.4 kg (116 lbs) |
| 5′ 4″ | 162.6 cm | 59.6 kg (131 lbs) | 55.8 kg (123 lbs) |
| 5′ 6″ | 167.6 cm | 63.5 kg (140 lbs) | 59.2 kg (131 lbs) |
| 5′ 8″ | 172.7 cm | 67.4 kg (149 lbs) | 62.5 kg (138 lbs) |
| 5′ 10″ | 177.8 cm | 71.2 kg (157 lbs) | 65.9 kg (145 lbs) |
| 6′ 0″ | 182.9 cm | 75.0 kg (165 lbs) | 69.3 kg (153 lbs) |
| 6′ 2″ | 188.0 cm | 78.9 kg (174 lbs) | 72.7 kg (160 lbs) |
| 6′ 4″ | 193.0 cm | 82.7 kg (182 lbs) | 76.1 kg (168 lbs) |
Frequently Asked Questions
What is a healthy body weight according to WHO and NHS standards?
According to WHO classifications and NHS standards, a healthy weight is defined by a Body Mass Index (BMI) ranging between 18.5 and 24.9. Our accurate free online ideal weight calculator displays this range for your height dynamically. For example, for an individual measuring 5 feet 10 inches (178 cm), the healthy BMI range corresponds to 58.6 kg to 78.9 kg (129 lbs to 174 lbs).
Which ideal weight formula is most accurate?
There is no single "most accurate" formula; each is used for different scenarios. The Devine formula (1974) is widely adopted in medical environments for calculating drug dosages, while the Robinson (1983) and Miller (1983) formulas are updated models designed to reflect average healthy weight distributions for men and women more closely.
Does my ideal weight target change as I get older?
Standard ideal weight equations (Robinson, Miller, Devine, Hamwi) do not factor in age. However, according to CDC guidelines, older adults may benefit from maintaining a slightly higher BMI (between 25 and 27) to protect against bone density loss, osteoporosis, and general frailty.
How do I switch between US Imperial units and UK/EU Metric units on this calculator?
At the top of our free online ideal weight calculator, you can toggle between "Metric (cm)" for UK/EU Metric units and "Imperial (ft·in)" for US Imperial units. The tool instantly recalculates your heights and bone frame sizes, displaying the final outputs in either kilograms (kg) or pounds (lbs) depending on your preference.
References & Medical Disclaimer
Ideal weight formulas (Hamwi, Devine, Robinson, Miller) correspond to clinical standards from the American Society of Health-System Pharmacists. Healthy BMI ranges correspond to World Health Organization (WHO) and Centers for Disease Control (CDC) guidelines. The estimates calculated by this tool are for educational reference and do not replace professional medical guidelines.