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Ideal Weight Calculator (น้ำหนักมาตรฐาน)

There is no single ideal weight. Every medical formula gives a slightly different number, and your frame, age and muscle mass matter too. This tool runs the eight most widely used formulas, including the "height minus 100" rule taught in Thailand, plots them on one chart and turns them into a sensible range of a few kilos, always inside the healthy BMI zone used for Asian adults (18.5 to 22.9). Add your current weight to see the gap, without judgement, and how long it would take at a gentle pace of 0.25 to 0.5 kg a week.

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Your measurements

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Your realistic range

52.5 to 56 kg

The middle of the eight formulas, inside the Asian healthy BMI zone.

52.5–564050607080
UnderweightHealthy zoneOverweightObesity level 1Obesity level 2
  • Healthy BMI zone (18.5 to 22.9): 47.4 to 58.6 kg
  • The formulas range from 51 to 57.2 kg (average 54.2 kg).
  • Medium frame assumed (add your wrist size to estimate it).

The eight formulas side by side

The green band is the healthy BMI zone, the dark band your realistic range.

  • average54.2

Thai formula (น้ำหนักมาตรฐาน) · 54 kgHeight minus 100 (men), minus 100 then 10% (women).

Silhouette

Add your current weight to compare both silhouettes.

Your weight today

Add your current weight (optional) to see the gap and how long it would take at a gentle pace.

To estimate your needs:Calorie calculatorBMI calculator

Thai น้ำหนักมาตรฐาน formula

Textbook version
54 kg
160 − 100 − 10%
"Height minus 110" variant
50 kg
160 − 110

Normal zone by this rule (90% to 110%): 48.6 to 59.4 kg

Thai sources vary: the tool uses the version taught in nutrition textbooks.

Target waist size

Under 80 cm

  • Half your height: 80 cm
  • Asian limit (IDF): 80 cm

Ideal weight chart by height

Heights close to yours: Female, age 30, same frame.

Suggested weight for heights close to 160 cm (Female)
Height (cm)Realistic rangeThai formula
15447 to 51.5 kgHealthy BMI: 43.9 to 54.3 kg48.6
15649 to 53 kgHealthy BMI: 45 to 55.7 kg50.4
15850.5 to 55 kgHealthy BMI: 46.2 to 57.2 kg52.2
160you52.5 to 56 kgHealthy BMI: 47.4 to 58.6 kg54
16254 to 57.5 kgHealthy BMI: 48.6 to 60.1 kg55.8
16456 to 59 kgHealthy BMI: 49.8 to 61.6 kg57.6
16657 to 60 kgHealthy BMI: 51 to 63.1 kg59.4

Same calculation as your result above, rounded to the nearest half kilo. The light bar is the healthy BMI zone, the dark bar the realistic range.

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Ideal Weight Calculator (น้ำหนักมาตรฐาน)

How it works

  1. The American formulas start from a base weight for 5 feet (152.4 cm) and add a little for every inch (2.54 cm) above it. Devine (1974): 50 kg for men and 45.5 kg for women, plus 2.3 kg per inch. Robinson (1983): 52 kg plus 1.9 kg per inch, or 49 kg plus 1.7 kg for women. Miller (1983): 56.2 kg plus 1.41 kg, or 53.1 kg plus 1.36 kg. Hamwi (1964): 48 kg plus 2.7 kg, or 45.5 kg plus 2.2 kg. These formulas were designed to help dose some medicines in hospital, so treat them as reference points, not goals. Below 152 cm they are extended downwards and become less reliable.

  2. The European formulas work directly in centimetres. Broca (1871) simply said "height minus 100"; the adjusted version most used today takes off 10% for men and 15% for women. Lorentz (1929) also subtracts the height above 150 cm divided by 4 for men, or by 2.5 for women (the most widely cited divisor; a few sites divide by 2). Creff, a French nutritionist, adds a tenth of your age to height minus 100, then multiplies by 0.9 and by a frame factor. It is the only one that takes age into account.

  3. In Thailand, nutrition textbooks and university courses (for example at Rajamangala University of Technology Phra Nakhon) teach the น้ำหนักมาตรฐาน rule: height minus 100 for men, and height minus 100 then minus 10% for women. A weight between 90% and 110% of that figure counts as normal. Many popular Thai websites use a simpler version for women, "height minus 110", and a few say "minus 105". Since sources disagree, the tool uses the textbook version, which is the one most often found in teaching material, and shows the "minus 110" variant next to it so you can compare.

  4. The healthy BMI zone is the one the World Health Organization proposed for the Asia-Pacific region in 2000, which Thailand's Department of Health (กรมอนามัย) uses: 18.5 to 22.9. From 23 it counts as overweight, from 25 as obesity level 1 and from 30 as level 2. These cut-offs are lower than the international ones (25 and 30) because, at the same BMI, Asian adults tend to carry more abdominal fat and have a higher risk of diabetes. After 65, several studies (including the 2014 meta-analysis by Winter and colleagues) suggest that a slightly higher weight is not harmful, so the tool extends the upper limit to a BMI of 24.9 and tells you so.

  5. The realistic range works like this: the tool takes the eight results, keeps the middle half (from the first to the third quartile, so that extreme values do not pull it around), brings it inside the healthy BMI zone and widens it to at least 3 kg if needed. Frame size comes from the ratio of height to wrist size (Grant's 1980 cut-offs, used by the US National Library of Medicine's MedlinePlus). A small frame lowers the Hamwi and Creff results by 10% and a large frame raises them by 10%, as their authors intended. Without a wrist measurement, a medium frame is assumed.

  6. Waist size often tells you more than weight. Thailand's Department of Health recommends a waist smaller than half your height (under 80 cm if you are 160 cm tall), and the International Diabetes Federation sets an Asian limit of 90 cm for men and 80 cm for women. If you want to change your weight, most health services recommend 0.25 to 0.5 kg a week, which protects muscle and is easier to keep up. This tool is not meant for children and teenagers, pregnant or breastfeeding women, or very muscular athletes, for whom BMI and these formulas are misleading. For any health question, please talk to a doctor or a dietitian.

These tools give general information. They do not replace the advice of a doctor or a qualified professional.

Go furtherNutrition & detox

Frequently asked questions

What is the ideal weight for 160 cm?
For a woman who is 160 cm tall, the Asian healthy BMI zone runs from about 47.5 to 58.5 kg and the formulas cluster around 52 to 56 kg; the Thai textbook formula gives 54 kg. For a man of 160 cm, the formulas give roughly 54 to 60.5 kg, inside the same BMI zone. Add your age and wrist size for a more personal range.
How is น้ำหนักมาตรฐาน (standard weight) calculated in Thailand?
The rule taught in Thai nutrition textbooks is height in centimetres minus 100 for men, and height minus 100 then minus 10% for women. A woman who is 160 cm tall gets 160 − 100 − 6 = 54 kg. You will also see "height minus 110" for women online, which gives 50 kg for 160 cm. The tool shows both.
Why is normal BMI 18.5 to 22.9 in Thailand instead of 24.9?
In 2000 the WHO proposed lower cut-offs for Asia-Pacific populations because, at the same BMI, they tend to have more fat around the waist and a higher risk of diabetes and heart disease. Thailand's Department of Health uses these cut-offs: overweight from 23 and obesity from 25.
Which ideal weight formula is the most accurate?
None of them is "the right one". Devine and Robinson were built for dosing medicines, Broca and Lorentz are old rules of thumb and Creff adds age. That is why the tool compares them and keeps the middle of their results inside the healthy BMI zone, rather than giving one number.
How do I find my frame size from my wrist?
Measure around your wrist just above the bone with a soft tape, then divide your height by that number. For women, a result above 11 means a small frame, 10.1 to 11 a medium frame and below that a large frame. For men, the cut-offs are 10.4 and 9.6. The tool does the maths for you.
How many kilos a week is safe to lose or gain?
Most health services suggest 0.25 to 0.5 kg a week, or 1 to 2 kg a month. Faster than that, people often lose muscle and regain the weight. The tool shows how long either pace would take, and our calorie and TDEE calculators help you estimate your needs. Talk to a health professional before any big change.
Is this calculator suitable for children, pregnant women or athletes?
No. Under 18, weight is followed on growth charts by age and sex. During pregnancy, weight gain is monitored with your doctor or midwife. For very muscular athletes, weight and BMI overestimate body fat, so waist size and a professional's opinion are more useful.

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