Body weight formulas give a target weight from your height and sex. For a man who is 180 cm tall, four common formulas give 71.5 to 77.3 kg, with an average of 74.1 kg. This calculator shows all four so you can see the spread, not just one number.
Each formula starts at a base weight for someone 5 feet (152.4 cm) tall. It then adds a set amount for each inch above that. The Devine formula, for example, gives men 50 kg plus 2.3 kg per inch. Robinson, Miller, and Hamwi use different starting points and steps. That is why they agree closely at average heights and drift apart for very tall people. The table below shows the average and range for common heights.
The formulas were not made to tell healthy people what to weigh. Devine published his in 1974 to help dose medicines, and it is still used in hospitals for that. Treat the results as a rough reference point. They also leave a lot out. No formula here counts muscle, frame size, age, or body fat. A strong person can be healthy well above these numbers. The formulas only apply from 152 cm (5 feet) upward, and the tool shows a note instead of a result below that.