Converting Height
Centimetres = (Feet × 12 + Inches) × 2.54
Total inches = Centimetres ÷ 2.54 Feet = Total inches ÷ 12
The inch has been defined as exactly 25.4 mm since the international agreement of 1959, so these conversions are exact rather than approximate.
The usual mistake is treating 5 feet 10 inches as 5.10 feet. Inches are twelfths: 5'10" is 5.833 feet, or 177.8 cm.
Common Heights
| Feet and inches | Inches | Centimetres | Metres |
|---|---|---|---|
| 4' 10" | 58 | 147.3 | 1.47 |
| 5' 0" | 60 | 152.4 | 1.52 |
| 5' 2" | 62 | 157.5 | 1.57 |
| 5' 4" | 64 | 162.6 | 1.63 |
| 5' 6" | 66 | 167.6 | 1.68 |
| 5' 8" | 68 | 172.7 | 1.73 |
| 5' 10" | 70 | 177.8 | 1.78 |
| 6' 0" | 72 | 182.9 | 1.83 |
| 6' 2" | 74 | 188.0 | 1.88 |
| 6' 4" | 76 | 193.0 | 1.93 |
| 6' 6" | 78 | 198.1 | 1.98 |
Predicting a Child's Adult Height
The mid-parental method is the standard clinical estimate. Average the two parents' heights, then adjust for the child's sex:
Boy: (Mother + Father) ÷ 2 + 6.5 cm
Girl: (Mother + Father) ÷ 2 − 6.5 cm
The 6.5 cm adjustment is half the average adult height difference between men and women, which is about 13 cm.
The prediction carries a genuine margin of about ±8.5 cm — roughly ±3.5 inches. Two-thirds of children finish within that range of the estimate, which means one in three does not. It is a reasonable expectation, not a forecast.
What Determines Adult Height
| Factor | Contribution |
|---|---|
| Genetics | ~80% of the variation between individuals |
| Nutrition in childhood | The largest environmental factor |
| Sleep | Growth hormone is released mainly during deep sleep |
| Childhood illness | Chronic illness can reduce final height |
| Hormonal conditions | Thyroid and growth hormone disorders |
Height is polygenic — influenced by hundreds of genetic variants, none individually large. That is why tall parents usually but not always have tall children, and why children tend to fall between their parents' heights rather than matching either.
Growth Timeline
| Stage | Typical growth |
|---|---|
| Birth to 1 year | ~25 cm |
| 1 to 2 years | ~12 cm |
| 2 years to puberty | 5–6 cm a year |
| Growth spurt, girls (10–14) | 8–9 cm a year at peak |
| Growth spurt, boys (12–16) | 9–10 cm a year at peak |
| After the spurt | Slows, then stops |
Girls typically reach final height around 14–16, boys around 16–18, when the growth plates in the long bones fuse. A useful rule: girls grow roughly 5–7.5 cm more after their first period.
Average Adult Heights
| Country | Men | Women |
|---|---|---|
| Netherlands | 183.8 cm (6'0") | 170.4 cm (5'7") |
| Germany | 179.9 cm (5'11") | 166.2 cm (5'5") |
| United Kingdom | 177.5 cm (5'10") | 164.4 cm (5'5") |
| United States | 175.3 cm (5'9") | 161.5 cm (5'4") |
| Turkey | 174.0 cm (5'9") | 161.4 cm (5'4") |
| Brazil | 173.6 cm (5'8") | 160.9 cm (5'3") |
| China | 171.8 cm (5'8") | 159.7 cm (5'3") |
| India | 164.9 cm (5'5") | 152.6 cm (5'0") |
Average heights have risen substantially over the past century wherever childhood nutrition improved — Dutch men gained about 20 cm in 150 years — which is the clearest evidence that environment matters alongside genetics.
You Are Taller in the Morning
Spinal discs compress under load through the day, so most people lose 1–2 cm between waking and evening and recover it overnight. Height measurements for medical records are taken in the morning for this reason, and it is why an evening measurement can disagree with a clinic's figure.
Frequently Asked Questions
How tall will my child be?
Enter both parents' heights above. Expect a range of about ±8.5 cm around the prediction rather than a single number.
Can anything increase adult height after growth stops?
No. Once the growth plates fuse, typically by the late teens, height is fixed. Posture, core strength and spinal health can recover a centimetre or two of lost height, but they do not add growth.
How do I convert 5'10" to cm?
(5 × 12 + 10) × 2.54 = 70 × 2.54 = 177.8 cm.
Why do I measure differently at different times?
Spinal compression through the day, plus posture and whether shoes are worn. Measure barefoot, first thing in the morning, standing against a wall with heels together.