This hair growth calculator is designed to estimate how long their hair might grow in months, weeks, days and years in inches and cm.
A woman with shoulder-length hair (about 14 inches) and wants to grow it to 17 inches, it would take approximately 6 months for additional 3 inches of growth.
To grow 3 inches of hair: Time = 3 inches ÷ 0.5 inches/month = 6 months
To grow 30 inches of hair: Time = 30 inches ÷ 0.5 inches/month = 60 months (or 5 years)
To grow 2 inches of hair: Time = 2 inches ÷ 0.5 inches/month = 4 months
Hair Growth Calculator
| Starting Length | Growth Rate | Time Period | Ending Length |
|---|---|---|---|
| 5 inches | 0.5 in/mo | 1 week | 5.125 inches |
| 10 inches | 0.5 in/mo | 8 weeks | 11 inches |
| 15 cm | 1.27 cm/mo | 15 weeks | 19.75 cm |
| 20 cm | 1 cm/mo | 26 weeks | 26.5 cm |
| 4 inches | 0.25 in/mo | 12 weeks | 4.75 inches |
| 8 inches | 0.75 in/mo | 20 weeks | 11.75 inches |
| 10 cm | 1 cm/mo | 5 weeks | 11.25 cm |
| 18 cm | 1.5 cm/mo | 45 weeks | 51.75 cm |
Monthly Average Hair Growth Chart
| Month | Average Growth (inches) | Average Growth (cm) |
|---|---|---|
| 1 | 0.5 | 1.27 |
| 2 | 1.0 | 2.54 |
| 3 | 1.5 | 3.81 |
| 4 | 2.0 | 5.08 |
| 5 | 2.5 | 6.35 |
| 6 | 3.0 | 7.62 |
| 7 | 3.5 | 8.89 |
| 8 | 4.0 | 10.16 |
| 9 | 4.5 | 11.43 |
| 10 | 5.0 | 12.70 |
| 11 | 5.5 | 13.97 |
| 12 | 6.0 | 15.24 |
Hair Growth Calculation Formula
The basic formula for calculating hair growth is:
Hair Growth = Growth Rate × TimeWhere:
- Growth Rate is typically measured in inches or centimeters per month
- Time is the number of months (or converted to months if given in days or years)
If we assume an average growth rate of 0.5 inches per month and want to calculate growth over 4 months:
Hair Growth = 0.5 inches/month × 4 months = 2 inches
How to Calculate Hair Growth?
Determine the average growth rate (typically 0.5 inches or 1.27 cm per month)
Identify the time period for calculation
Multiply the growth rate by the time period
Calculate hair growth for 9 months
Average growth rate: 0.5 inches/month
Time period: 9 months
Hair Growth = 0.5 × 9 = 4.5 inches
How Long Does Hair Grow in 1 Week?
In one week, hair typically grows about 0.125 inches or 0.3175 cm.
To calculate weekly growth, we need to convert our monthly rate to a weekly rate:
0.5 inches/month ÷ 4 weeks = 0.125 inches/week
How Long Will My Hair Grow in 3 Months?
Hair Growth = 0.5 inches/month × 3 months = 1.5 inches
If your hair is currently 12 inches long, after 3 months of growth, it would be approximately 13.5 inches long.
How Much Does Your Hair Grow in 100 Days?
First, convert days to months: 100 days ÷ 30 days/month ≈ 3.33 months
Now apply the formula: Hair Growth = 0.5 inches/month × 3.33 months ≈ 1.67 inches
If your hair is 10 inches long today, after 100 days, it would be about 11.67 inches long.
How Long Does It Take to Grow 2 Inches of Hair?
To find the time, we rearrange our formula: Time = Desired Growth ÷ Growth Rate
Time = 2 inches ÷ 0.5 inches/month = 4 months
You currently have a 5-inch bob and want it to reach 7 inches, it would take approximately 4 months to achieve this length.
How Long Does It Take to Grow 10 Inches of Hair?
Time = 10 inches ÷ 0.5 inches/month = 20 months
You’re starting with a very short pixie cut and want to grow your hair to mid-back length (about 14 inches), it would take around 20 months to grow the additional 10 inches needed.
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