Example 1
- Height: 175 cm
- Sex: male
68.8 kg
175 cm in a man gives 68.8 kg Lorentz, BMI at that mass about 22.5.
Ideal body weight calculator
Type height and pick sex. Lorentz returns one mass, rounded to 0.1 kg. A 175 cm man gets 68.8 kg. Current weight is optional context, not an input to Lorentz itself.
Lorentz from height and sex. Mass category from the weight you actually have lives on the BMI calculator. Devine is a different formula on a different page.
Result
Height (cm), Sex, Current mass (kg) and Age (years, optional). Lorentz weight shows up here.
How it works
Lorentz uses height and sex alone. For a man you subtract 100, then subtract (height minus 150) divided by 4. For a woman the same parenthesis is divided by 2. The calculator rounds to 0.1 kg. One hundred seventy-five centimeters in a man is 68.8 kg, because 75 minus 6.25. One hundred sixty-five centimeters in a woman is 57.5 kg. One hundred eighty centimeters in a man is 72.5 kg.
People look up “ideal weight” as if it were a bathroom-scale target. The formula is a historical sketch, not a clinic order. Two people with the same height and sex get the same number even if age, training, and body-fat percent differ. Devine is another line on another URL. This calculator does not mix two old tables.
Current mass, age, and activity are optional. Current mass shows a delta versus Lorentz and BMI from that mass. Age and PAL, when you fill them together with sex, add a Mifflin and TDEE sketch. Lorentz itself still depends only on centimeters and the male or female choice. You can click Calculate with the context block empty and still get the formula kilograms.
The US switch converts inches and pounds with 2.54 and 0.453592. Pounds apply to current mass. If you convert 170 cm with 2.54 and type those inches for a woman, Lorentz stays 60.0 kg. A different inch count is a different height, so a different formula mass.
BMI on the sibling page categorizes the mass you actually have. Lorentz proposes one mass from height alone. FFMI needs a body-fat percent and describes lean density. Navy estimates that percent from girths. Three different sketches, one height, and none of them is “the only true weight.”
More points on the same line: a 160 cm woman is 55.0 kg, a 185 cm man is 76.3 kg, a 155 cm woman is 52.5 kg, a 190 cm man is 80.0 kg. Type height, pick sex, click Calculate. Treat 68.8 kg as a school-formula result, not as an order to lose weight.
How to use
- Type height in centimeters or inches, matching the units switch, and pick sex.
- Click Calculate even if current mass is empty. Lorentz runs from height and sex alone, to 0.1 kg.
- If you want a delta and BMI, add current mass. Age and activity add a TDEE sketch, but they do not move the Lorentz kilograms.
- Check 175 cm in a man: 68.8 kg. A 165 cm woman is 57.5 kg, and a 180 cm man is 72.5 kg.
- Open BMI for a WHO band from the mass you actually have. Leave Devine on its own page. This calculator is Lorentz only.
Formula
Male: kg = cm - 100 - (cm - 150) / 4
Female: kg = cm - 100 - (cm - 150) / 2
Rounded to 0.1 kg. Lorentz, not Devine and not WHO BMI.
Lorentz and one mass from height
Lorentz returns one mass from height and sex, rounded to 0.1 kg. A 175 cm man gets 68.8 kg. Current weight does not enter that line.
- Lorentz
- kg = cm − 100 − (cm − 150) / 4 for a man, / 2 for a woman. 175 − 100 − 25/4 = 68.8. Not Devine and not a WHO BMI band.
- Devine
- Another ideal-weight formula this calculator does not run. At 175 cm you still see 68.8 from Lorentz, with no Devine table.
Examples
Example 2
- Height: 165 cm
- Sex: female
57.5 kg
165 cm in a woman gives 57.5 kg, because (cm minus 150) is divided by 2.
Example 3
- Height: 180 cm
- Sex: male
72.5 kg
180 cm in a man gives 72.5 kg Lorentz.
Example 4
- Height: 170 cm
- Sex: female
60.0 kg
170 cm in a woman gives 60.0 kg. That is not a WHO BMI category.
Example 5
- Height: 160 cm
- Sex: female
55.0 kg
160 cm in a woman gives 55.0 kg from height and sex alone.
Example 6
- Height: 185 cm
- Sex: male
76.3 kg
185 cm in a man gives 76.3 kg after rounding to 0.1 kg.
Example 7
- Height: 155 cm
- Sex: female
52.5 kg
155 cm in a woman gives 52.5 kg. Lorentz, not a clinician’s order.
Example 8
- Height: 190 cm
- Sex: male
80.0 kg
190 cm in a man gives 80.0 kg. A different height gives a different number, same formula.
Frequently asked questions
Why does a 175 cm man get 68.8 kg?
Because 175 minus 100 minus (25 / 4) is 68.75, rounded to 68.8 kg. Devine is a different table on a different URL.
Why is a 165 cm woman 57.5 kg, not the male figure?
For a woman you divide (cm minus 150) by 2, not by 4. At 165 cm that is 57.5 kg. Sex changes only that divisor.
Does current mass change 72.5 kg for a 180 cm man?
Not the Lorentz number itself. Current mass adds a delta and BMI from that mass. Lorentz stays 72.5 kg at the same height and sex.
Why are there age and activity fields?
Only for optional Mifflin and TDEE. You can skip them and keep the Lorentz kilograms alone.
Is this the Devine formula?
No. This page is Lorentz. Devine has another history and its own address. One card, one formula.
Is 55.0 kg at 160 cm in a woman a diet order?
It is the formula value from height and sex. Someone at that height can be fine at another mass. BMI from real mass talks about a category. Lorentz talks about one number.
Do inches change 60.0 kg for a 170 cm woman?
No, if you convert 170 cm with 2.54 and type those inches. A different inch count is a different height. Pounds apply only to current mass.
How is Lorentz different from BMI?
BMI categorizes the mass you have, over height squared. Lorentz proposes one mass from height and sex alone.
Does FFMI or Navy replace Lorentz?
No. FFMI needs a body-fat percent. Navy estimates that percent from girths. Lorentz does not know girths.
What is Lorentz at 190 cm in a man?
80.0 kg. At 185 cm it is 76.3 kg, and at 155 cm in a woman it is 52.5 kg. Same formula line, different height.
Knowledge sources
Lorentz from height and sex. This is not a WHO band and not a clinic goal.
Page updated in 2026.