Hair Growth Calculator
Enter your current and target length to estimate how long your hair will take to get there, or how much it will grow in a given time.
Average hair growth: 1.25 cm/month. Enter a time period, or your current and target length.
Growth time (months)
Growth length (cm)
Current and target length
Current length (cm)
Target length (cm)
Results are based on statistical averages. Trims, chemical treatments and health conditions can affect the growth rate.
How Many Centimetres Does Hair Grow per Month on Average?
Human hair grows 1 to 1.5 cm a month on average, about 12–15 cm a year. The calculator uses 1.25 cm a month, the midpoint of this range. The rate varies with age, genetics, nutrition and hair care habits.
Factors That Affect Hair Growth
- Genetics: the biggest factor. It sets the growth rate and how long the anagen phase lasts.
- Nutrition: a lack of protein, iron, zinc or biotin 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 speed up slightly in summer.
Tips to Help Hair Grow Faster
You cannot grow hair faster than your genetics allow, but good habits help you reach that limit. A diet rich in protein and iron, regular scalp massage to improve circulation, less heat styling and using conditioner are among the most effective habits. Managing stress and sleeping enough also help the hair cycle.
Key Factors That Affect Hair Growth
Hair grows 1–1.5 cm a month on average, but the rate varies a lot with genetics, age, diet and hair care routine. A lack of protein, biotin, zinc or iron can trigger hair loss and slow growth. Regular care reduces breakage at the ends and helps you keep length over time.
Hair Growth Phases and Growth Rate
The hair cycle has three phases. In the anagen (growth) phase, hair grows actively for 2–6 years; this phase does the most to set how long hair can get. The catagen (transition) phase lasts 2–3 weeks, and the follicle shrinks. The telogen (resting) phase lasts about 3 months, while the hair gets ready to shed.
Effect of Nutrition and Vitamin Supplementation on Hair Growth
Low biotin, iron, zinc or vitamin D directly affects growth rate. Hair is made mostly of a protein called keratin, so daily protein intake matters for hair health. During poor nutrition or rapid weight loss, shedding can increase and growth can slow. A balanced diet, plus supplements guided by blood tests when needed, is recommended.
Hair Care Routine: Practices That Support Growth
Regular scalp massage improves blood flow and nourishes the follicles. Keep heat and chemical treatments to a minimum, and trim the ends regularly to prevent breakage and split ends. Not combing wet hair and braiding or loosely tying it at night reduce breakage while you sleep, which helps you keep length over time.