Hair Growth Calculator
Calculate how long until you reach your target length or how much your hair will grow in a given time.
Average hair growth: 1.25 cm/month. Fill any field.
Growth time (mos)
Growth length (cm)
Current and final length
Current length (cm)
Final length (cm)
Hair Growth Calculator: When Will Your Hair Reach Target Length?
You've decided to grow your hair but don't know when it will reach your desired length. Or the opposite: some time has passed and you're curious how much it has grown. The hair growth calculator answers both questions using the average growth rate as its baseline.
How Fast Does Hair Grow on Average?
Human hair grows on average between 1 and 1.5 cm per month — about 12–15 cm per year. The calculator uses 1.25 cm/month as its baseline, the midpoint of this range. Growth rate varies by age, genetics, nutrition and hair care habits.
Hair growth follows three phases: anagen (growth), catagen (transition) and telogen (resting). The active growth phase, anagen, can last 2–7 years — this genetic limit determines how long your hair can ultimately grow.
How to Use the Calculator
Time → Growth Length
Enter a value in months in the "Growth time" field. If you also enter your current length, the calculator shows the estimated total length you'll reach after that period.
Target Length → Time
Enter your current length and target length. The tool calculates how long it will take to close that gap at the average growth rate.
Example Scenarios
| Start | Target | Time |
|---|---|---|
| ~5 cm (pixie) | ~35 cm (shoulder) | ~24 months |
| ~15 cm (short) | ~50 cm (medium-long) | ~28 months |
| ~30 cm (medium) | ~60 cm (long) | ~24 months |
| 0 cm (shaved) | ~20 cm (short) | ~16 months |
Results are based on statistical averages. Trims, chemical treatments and health conditions may affect growth rate.
Factors That Affect Hair Growth
- Genetics — the most decisive factor; determines growth rate and anagen phase length.
- Nutrition — protein, iron, zinc and biotin deficiency slows growth.
- Hormonal changes — pregnancy, thyroid disorders and menopause affect the hair cycle.
- Hair care — regular moisturising and avoiding heat damage reduce breakage.
- Season — growth may slightly accelerate in summer months.