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LJ HairLab

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Hair Shrinkage Calculator

This hair shrinkage calculator turns your stretched and dry lengths into a shrinkage percentage, and shows the true length your curls are hiding.

Measure the same section twice

in

Gently pull one curl straight and measure root to tip.

in

The same curl, fully dry, measured as it sits.

in

Dry and unstretched. Leave empty to skip.

How to use the Hair Shrinkage Calculator

  1. Measure one curl stretched

    On dry hair, gently pull one curl or coil straight and measure it from root to tip. Enter that as your stretched length.

  2. Measure the same curl as it sits

    Let the curl spring back and measure it again without pulling. Enter that as your dry, unstretched length.

  3. Add the length you want your hair to look

    This is optional. Enter a dry length and the calculator works out the stretched length you need to reach it.

  4. Press “Calculate my shrinkage”

    You get your shrinkage percentage, a low to very high band, your true length and the length the curl is hiding.

How to use the Hair Shrinkage Calculator (49 s)

How the hair shrinkage calculator works

Shrinkage is the difference between how long your hair really is and how long it looks once the curls and coils have sprung up. The calculator needs two measurements of the same section: pulled straight, and dry as it sits. 

shrinkage = 1 − dry length ÷ stretched length
stretched length needed = length you want to see ÷ (1 − shrinkage)

How to measure

Work on fully dry hair with no stretching style in it, such as a wash-and-go. Pick one curl at the crown, hold a tape measure at the root and note where the tip sits. Then pull the same curl gently until it is straight, without yanking, and read the tape again. The crown, nape and edges often shrink by different amounts, so measure two or three spots if you want the full picture.

The four bands

The result is labelled low (under 25%), moderate (25–50%), high (50–70%), very high (over 70%). The bands only describe the number. None of them is better than another, and shrinkage is a sign of elasticity, not a problem: hair that can coil back up is hair that can stretch without snapping.

The reverse helper

If you enter the length you want your hair to look, the calculator turns the formula around. With 60% shrinkage only 40% of your length shows, so to look 8 inches long you need 20 in of stretched hair. This assumes your shrinkage stays the same as your hair grows, which is roughly true but not exact, because longer hair is heavier and hangs a little straighter.

What it cannot tell you

Shrinkage does not identify your curl type. The table below gives typical ranges from wavy to 4c, but they are rules of thumb and they overlap. Curl shape varies widely from person to person and even across one head, so take the hair type quiz for that. Shrinkage also does not measure health or growth. To see where your true length falls on your body, open the hair length chart.

Typical shrinkage by curl type

Curl type Pattern Typical shrinkage Band 10 in stretched looks about
2a–2c Wavy 5–20% Low 8.8 in
3a Loose curls 20–30% Moderate 7.5 in
3b Springy curls 25–40% Moderate 6.8 in
3c Tight curls 35–50% Moderate 5.8 in
4a Coils 50–65% High 4.3 in
4b Z-pattern coils 60–70% High 3.5 in
4c Tightest coils 70–85% Very high 2.3 in

Rules of thumb from the natural hair community, not measurements. Your shrinkage can sit outside the range for your curl type.

Dry length you see at each shrinkage level

Stretched length 25% shrinkage50% shrinkage70% shrinkage
6 in 4.5 in3 in1.8 in
10 in 7.5 in5 in3 in
14 in 10.5 in7 in4.2 in
18 in 13.5 in9 in5.4 in
22 in 16.5 in11 in6.6 in

1 in = 2.54 cm.

Frequently asked questions

How do I calculate hair shrinkage?
Measure one curl pulled straight, then measure the same curl dry and unstretched. Divide the dry length by the stretched length and subtract the answer from 1. Hair that is 10 inches stretched and 4 inches dry has 60% shrinkage. The hair shrinkage calculator above does the math for you.

Is shrinkage a sign of healthy hair?
Shrinkage shows that your hair is elastic: it stretches when wet or pulled and springs back as it dries. That spring is a good sign, not damage. Curls that suddenly stop shrinking and hang limp can be a sign of heat or chemical damage.

How much shrinkage is normal for 4c hair?
A common rule of thumb is 70% or more, which means 4c hair can show less than a third of its real length. These figures are estimates passed around the natural hair community, not measurements, and your own number can sit outside them.

How do I find my true hair length?
Your true length is your stretched length. Gently pull a section straight and measure from root to tip, or measure after a blow-out or in a stretched style such as twists or braids. Use the same method every time so your numbers can be compared.

Can I reduce shrinkage?
You can stretch your hair for a while with styles such as twist-outs, braid-outs, banding or African threading, or with a blow-dryer on low heat. The curl returns when the hair gets wet. You cannot change your curl pattern for good without heat damage or a chemical service.

Does shrinkage mean my hair is not growing?
No. Hair that shrinks 60% only shows 4 of every 10 inches it grows, so progress is easy to miss. Track your stretched length once a month instead. The hair growth calculator can estimate when you will reach a goal length.

Why is my shrinkage different from one day to the next?
Shrinkage changes with how wet the hair is, the humidity in the air, the products you used and how the hair was styled. Different parts of your head also shrink by different amounts. Measure fully dry hair in the same spot to get numbers you can compare.

Sources

Last data update:

  1. Loussouarn G, Lozano I, Panhard S, et al. Diversity in human hair growth, diameter, colour and shape. An in vivo study on young adults from 24 different ethnic groups observed in the five continents. Eur J Dermatol. 2016;26(2):144-154. Growth rate, diameter and curl shape vary widely between and within groups.

How we research and update pages: editorial policy. Spotted an error? Tell us.

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