Height Calculator: Convert, Compare & Predict Height

Quick Answer: This tool converts height between feet/inches and centimeters instantly, compares a person’s height to typical age-based growth patterns using CDC/WHO data, and estimates a child’s future adult height using the mid-parental and Khamis-Roche methods. Predictions are estimates with a margin of error of roughly ±4–8 cm, not guarantees.

A height calculator helps you do three things people actually care about: convert height units, compare height with typical age-based growth patterns, and estimate future height using established prediction methods. Whether you’re filling out a school form, checking a sports profile, tracking growth at home, or simply curious, this page gives you quick results with the context to interpret them correctly.

CalculatorGeek’s height tool is built as a complete height hub:

• Understand what affects height — genetics, sleep, nutrition, and growth timing
• Convert feet/inches to centimeters (and back) in seconds
• Compare results with growth charts (median vs. mean trends)
• Predict a child’s possible adult height using parent-based and clinical estimation methods

Related tools: BMI Calculator

Convert Height Between Feet, Inches, and Centimeters

Most people use a height calculator because different systems are used in different places — medical forms, school records, sports profiles, or international documents. This tool accepts height naturally and returns an exact result without rounding errors.

The converter:

• Accepts feet and inches together (not just decimal feet)
• Converts instantly to centimeters
• Displays results clearly and consistently

Conversion standards used:

• 1 inch = 2.54 centimeters
• 1 foot = 12 inches = 30.48 centimeters

These values are internationally standardized (SI/imperial conversion definitions) and ensure consistent results across devices and platforms.

Common Height Conversions (Quick Reference)

How to Measure Height Correctly at Home

Even the most accurate calculator can’t help if the measurement itself is off. Small mistakes — shoes, posture, uneven floors — can change the result by a centimeter or more.

1. Measure barefoot on a hard, flat surface
2. Stand straight with heels close to the wall
3. Keep eyes looking forward (chin level)
4. Use a flat object (book or ruler) at a right angle on the head
5. Measure from the floor to the mark
6. Repeat once and use the average

Tip: Height can vary by up to about 1–2 cm over the course of a day because the spine compresses slightly while standing and moving. Measuring at the same time each day — morning is most consistent — improves accuracy.

Once you have measured your exact height, you can use our BMI calculator.

Height and Genetics — Why Family Traits Matter Most

When people talk about height, they usually say “it’s genetic” — and they’re largely right, though it’s worth being precise about what that means. Height isn’t controlled by one gene the way eye color roughly is. It’s polygenic, shaped by hundreds of genes, which is why:

• Two tall parents can have an average-height child
• Two average-height parents can have a tall child
• Siblings can end up noticeably different heights

A large twin study by Silventoinen et al. (2000, Behavior Genetics), based on nearly 8,800 adult Finnish twins, estimated heritability at roughly 78% in men and 75% in women — meaning genetics explains most, but not all, of the variation in adult height within a population. Heritability estimates run somewhat lower in some Asian and African populations, around 65%, reflecting differences in study populations and environmental variance rather than a different biological mechanism.

Why calculators use parent height: Parent-based tools try to approximate a child’s genetic “zone” rather than predicting one exact number. That’s the logic behind mid-parental and Khamis-Roche style estimates — simpler than a lab test, and generally more informative than age-only guesses.

Genetics still isn’t the whole story. A few things can shift how growth actually plays out even within a strong genetic range:

• Puberty timing (early vs. late bloomers)
• Long-term nutrition consistency
• Sleep patterns over years
• Health factors that affect hormones or absorption

If genetics is the blueprint, childhood conditions are the construction crew. Most children with supportive sleep, diet, and general health end up somewhere near their family’s height range — the calculator below helps show that range without overpromising a single number.

“How Tall Will I Be?” Estimating a Child’s Adult Height

Height prediction is not fortune-telling. It’s a data-informed estimate combining current age and height, sex-based growth patterns, family height, and population growth references. The result is best understood as a probable range, not a promise — two children with identical inputs can still end up different heights due to differences in growth timing, especially around puberty.

Why estimates shift as children grow:

• Early or late puberty — late bloomers may appear shorter for years, then catch up quickly
• Growth spurts — height gain happens in bursts, not steadily
• Lifestyle factors — long-term nutrition and sleep patterns matter more than short-term changes

How to interpret your result responsibly:

• Focus on the range, not the midpoint alone
• Compare results with growth charts, not classmates
• Look at trends over time, not one measurement

If a child’s estimated range drops sharply compared with earlier checks, or growth appears to slow noticeably, that’s a signal to talk to a pediatrician for clarity — not a reason to panic.

The Khamis–Roche Child Height Predictor

The Khamis–Roche method, published by Khamis and Roche in 1994 (Pediatrics), is one of the most widely referenced non-clinical methods for estimating a child’s adult height. It’s popular because it uses information families already know and requires no imaging or lab tests.

Inputs used:

• The child’s current age
• The child’s current height
• The child’s current weight
• The heights of both parents

How the Khamis-Roche Math Works: Unlike the simple mid-parental average, the Khamis-Roche method uses a complex algebraic regression equation: Adult Height = β0 + (β1 × Child's Current Height) + (β2 × Child's Current Weight) + (β3 × Mid-Parental Height). The “β” (beta) coefficients change entirely depending on the child’s exact age in half-year increments. Our calculator automatically applies the correct, peer-reviewed coefficients based on the age you input to deliver an accurate clinical-grade estimate.

By blending these with long-term population growth data, the method estimates a likely adult height range rather than a single fixed number.

Accuracy and applicability: The original Khamis-Roche coefficients were validated on children roughly ages 4–9 who were free of growth-related medical conditions and following a typical growth pattern. Estimates become less reliable outside that age range or when a child’s growth deviates significantly from typical patterns — a subsequent review by Wright and Cheetham (1999, Archives of Disease in Childhood) found parent-height-based predictors work reasonably well as a population-level tool but carry real individual-level uncertainty.

How to interpret your Khamis–Roche result:

• Treat the midpoint as a reference, not a target
• Pay attention to the upper and lower bounds shown
• Recheck periodically as new measurements become available

The Mid-Parental Height Formula

The mid-parental height method is a widely accepted baseline for estimating a child’s genetic height potential.

If using centimeters, the formula is:

• For Boys: Estimated Height = (Father’s Height + Mother’s Height + 13) ÷ 2
• For Girls: Estimated Height = (Father’s Height + Mother’s Height − 13) ÷ 2

If using inches, the formula is:

• For Boys: Estimated Height = (Father’s Height + Mother’s Height + 5) ÷ 2
• For Girls: Estimated Height = (Father’s Height + Mother’s Height − 5) ÷ 2

Step-by-Step Calculation Example

How we calculate genetic potential: Let’s assume a mother is 165 cm (approx 5’5″) and a father is 180 cm (approx 5’11”), and they want to estimate their son’s adult height.

• Step 1: Add both parents’ heights together. 180 + 165 = 345 cm
• Step 2: Add the male adjustment factor (13 cm). 345 + 13 = 358 cm
• Step 3: Divide by 2 to find the mid-parental estimate. 358 ÷ 2 = 179 cm

Result: The son’s estimated adult height is 179 cm (approx 5’10.5″). Most children will fall within a standard deviation range of ± 8.5 cm from this genetic midpoint.

Bone Age and Skeletal Maturity — A More Advanced Height Prediction

Bone age estimates skeletal maturity — how developed a child’s bones are compared to what’s typical for their calendar age. This matters because growth plates gradually close as skeletal maturity increases, and closure timing affects how much growth potential remains.

Important: Bone age cannot be determined by a website calculator. It’s assessed by clinicians using imaging (commonly a left-hand/wrist X-ray, evaluated with methods like Greulich-Pyle) and professional interpretation. Understanding the concept still helps parents interpret prediction results realistically — especially for a child who’s an early or late grower.

Chronological age vs. bone age:

• Chronological age = age on the calendar
• Bone age = how mature the skeleton appears for that age — it can run advanced (looks older than actual age) or delayed (looks younger)

A child who’s shorter than peers may still have substantial growth potential left if their bone age is delayed, while a child who had an early growth spurt may have less remaining growth even though they currently look tall. This is why two children with similar parent heights can end up growing quite differently, and why chart interpretation should weigh growth timing, not just current height.

Some advanced medical evaluations use bone age to better understand remaining growth potential. This tool does not calculate bone age and cannot replace professional assessment.

When professional guidance can help (calm, not alarming):

• Growth slows noticeably over time
• A child drops across growth percentiles
• Puberty timing seems unusually early or late
• There are persistent concerns about a child’s growth pattern

Clinicians evaluating unusual growth patterns may also assess hormone-related factors, such as growth hormone levels, as part of a broader workup.

Learn more: MedlinePlus (general health info) or NIH/NCBI overview pages

Growth Charts—How to Read the Attached Charts the Right Way

A height prediction is useful, but a chart answers the deeper question: is this height typical for this age? That context — not just a number — is what improves interpretation, and it’s also what separates a genuinely useful page from a bare calculator.

Median vs. mean (the key difference in the charts below):

Mean height = the mathematical average. Useful for broad comparison, though it can drift slightly in older adult age groups.

Median height = the middle value (50th percentile). Half the population at that age is taller, half shorter. This is usually the best “typical” reference because it’s less skewed by extremes.

Chart 1: Median Height by Age and Sex (US reference data)

Note: Median shows the midpoint height for each age—a strong “typical” benchmark. Source: CDC Growth Charts.

Chart 2: Mean Height by Age and Sex (US average)

Mean shows the average height. Small shifts in older age groups can reflect posture and mild spinal compression rather than actual growth change.

Note: Mean shows the statistical average. The slight decline in older age groups reflects mild spinal compression and demographic shifts. Source: CDC/NCHS National Health and Nutrition Examination Survey

How to read the trend, not just today’s point:

1. Find the age on the bottom axis, follow up to the male/female line
2. Read the height value where it meets the line
3. Compare the trend over time — a single measurement is a snapshot; a pattern over months or years is the real story

What the pattern typically looks like:

• Early childhood: faster growth early, then steadier
• Puberty window: growth accelerates — girls typically begin their spurt around ages 10–12 with peak growth velocity near age 12; boys begin roughly two years later, peaking around age 14
• Late teens: growth slows sharply as growth plates approach closure — commonly around ages 14–16 in girls and 16–18 in boys
• Adults: height stabilizes, with slight declines possible in later age groups

Growth charts are reference tools, not diagnoses. If a child’s growth pattern changes sharply — especially dropping across multiple percentiles — professional guidance can help clarify what’s going on.

References:

• CDC Growth Charts
• WHO Child Growth Standards

When Do Girls Typically Stop Growing?

There’s no single universal age, but the pattern is well documented: girls typically begin their pubertal growth spurt around ages 10–12, and growth plates in the long bones generally close by around age 14–16, after which additional height gain is minimal. That’s why many girls reach near-adult height earlier than boys.

Use the height-by-age table above as context, not a target — height varies naturally, and being shorter or taller than the median doesn’t by itself mean anything is wrong. Averages also vary somewhat by country and dataset.

What actually matters more than the exact number:

• Consistent growth over time is usually reassuring
• A one-time “short” measurement often comes down to technique or timing
• Growth happens in spurts — quiet months followed by sudden change

If a child’s height trend drops sharply across percentiles, or growth slows noticeably over an extended period, that’s the moment professional guidance can help — without panic or assumptions.

When Do Boys Typically Stop Growing?

Boys tend to start their major growth spurt about two years later than girls — commonly beginning around age 12–13 and peaking near age 14 — and growth plates generally close by around age 16–18. That’s why two boys the same age can look like they’re in completely different growth phases while both are developing normally.

Reading the boys’ growth table:

• Values reflect typical population references, not individual destiny
• The table is most useful compared across several measurements over time
• Being below the median may simply mean a later-timed puberty, not a problem

What’s normal during the teen years:

• Growth often happens in spurts, not steady weekly increments
• Puberty timing determines whether a teen looks “early” or “late” relative to peers
• A consistent trend matters more than any single check

If growth slows dramatically or drops sharply across percentiles, that’s the appropriate moment to seek professional guidance.

How to Get Taller — What’s Realistic, What Helps, and What’s a Myth

The honest answer depends on one thing: whether you’re still growing. If growth plates are open (typically children and teens), healthy habits can help you reach your natural height potential. If growth plates have closed (most adults), you generally can’t increase bone length — but posture and measurement habits can change how tall you look and measure.

If you’re a teen or still growing, the goal is giving your body the best conditions to follow its growth plan:

• Consistent sleep — deep sleep supports growth-related hormone release; chronically short sleep may not support optimal growth
• Balanced nutrition — steady meals with protein, calcium-rich foods, fruit/vegetables, and hydration; long-term under-eating or poor micronutrient intake can affect development
• Regular activity — sports don’t stretch you taller, but they strengthen bones and support posture
• Healthy routines — long-term stress and irregular schedules can affect appetite and recovery during growth years

What to avoid: extreme diets during growth years, overtraining without recovery, and “height booster” supplements — these are largely unproven and often expensive.

If you’re an adult, growth plates have closed and bone length generally can’t be increased naturally. However, posture, strength, and measurement technique can meaningfully change your measured and perceived height:

• Posture improvements — a neutral spine alignment can change measured height slightly
• Strength and mobility — core and back strength plus hip mobility reduce a “collapsed” posture look
• Daily habits — years of hunching over screens compresses posture; correcting it can make a visible difference
• Consistent measurement — same time of day, barefoot, same method, to reduce variation

A simple, safe routine: wall stands with neutral head position, gentle chest-opening stretches, hip flexor mobility work, and core stability exercises (dead bug, plank variations). This doesn’t add bone length — it helps you use the height you already have.

Common myths worth clearing up:

• Myth: “Stretching makes adults permanently taller.”
  Reality: Stretching can improve posture and reduce tightness, but it doesn’t lengthen bones permanently.
• Myth: “A pill can add inches.”
  Reality: Most “height supplements” are unverified marketing. Nutrients help if there’s a deficiency—but they don’t override genetics.
• Myth: “Sports like basketball make you taller.”
  Reality: Taller people may gravitate toward those sports; the sport itself doesn’t create height.

FAQs

How do I convert feet and inches to centimeters?

To convert feet and inches to centimeters, multiply the feet by 30.48 and multiply the inches by 2.54, then add the two numbers together. For example, for someone who is 5’9″: (5 × 30.48) + (9 × 2.54) equals exactly 175.26 centimeters.

How accurate is a height prediction calculator for kids?

Height prediction calculators provide a realistic estimate range, not a guaranteed exact number. Most children will reach an adult height within 2 to 3 inches of their mid-parental genetic estimate, though variations in puberty timing, nutrition, and overall health can shift the final result.

Why does my height change between morning and night?

You measure slightly taller in the morning and shorter at night because the cartilage discs in your spine compress throughout the day due to gravity and daily movement. It is normal to lose up to half an inch (about 1 to 2 cm) of height by the evening.

What does “median height” mean on a growth chart?

Median height represents the exact middle value of a population for a specific age group, meaning it is the 50th percentile. If a child is at the median height, exactly half of the children their age are taller, and the other half are shorter.

Can adults get taller naturally?

Adults cannot naturally increase their bone length after their growth plates close, which typically happens by age 18 to 21. However, adults can often “regain” 1 to 2 inches of functional height by correcting poor posture, strengthening their core, and improving spinal alignment.

When should parents be concerned about a child’s growth?

Parents should consult a pediatrician if a child’s growth suddenly slows down or if their height drops significantly across multiple percentiles on a standard growth chart over time. A single short measurement is rarely a cause for concern, but a changing long-term trend warrants professional evaluation.

External references:

CDC Growth Charts (Height-for-age references)

WHO Child Growth Standards

MedlinePlus (General health information)

Data & Medical Disclaimer

This tool was built by our technical team and strictly adheres to our scientific data sourcing standards. The algorithms powering this calculator are based on peer-reviewed mathematical models (such as the Khamis-Roche method) and official CDC/WHO dataset standards. It is designed for educational estimation and growth-tracking purposes only. It is not a substitute for clinical evaluation, and we do not provide medical diagnoses. Always consult a pediatrician or healthcare provider for professional guidance on human growth and development.