Hair Color Numbers Explained: Find Your Shade (#1B, #2, #613)

Hair extensions are sold by numbers such as #1B, #4 or #613, and the codes can feel like a secret language. They follow a simple pattern once you know it, with one catch that trips up most first-time buyers.

In short: hair extension shade numbers run from dark to light. #1 is jet black, #1B off-black, #2 darkest brown, #4 to #8 the browns, #18 to #27 the dark and honey blondes, and #60 and #613 the lightest blondes. The catch is that there is no universal standard, so the same number can look different between brands.

How do hair color numbers work?

Hair color numbers work on a dark-to-light scale. Low numbers are the darkest shades and higher numbers are lighter. The system grew out of the level scale hairdressers use, where level 1 is black and level 10 is the lightest blonde, but extension brands later added their own codes such as #1B, #27, #60 and #613.

Two things follow from that history:

• The order is reliable. A #2 is always darker than a #6 within the same brand.
• The exact shade is not. One brand’s #4 can match another’s #6, so the number alone cannot tell you if a piece will match your hair.

What does each common shade number mean?

The table below shows how the most common codes are generally used and what our own shades look like.

Code	Common name	Looks like	Often suits
#1	Jet black	Deep black with a cool, blue-black depth	Hair dyed black
#1B	Natural black	Soft black, slight brown in sunlight	Most natural black hair
#2	Darkest brown	Near-black brown, warm in daylight	Very dark brown hair
#4	Dark brown	Rich chocolate brown	Dark brunette hair
#6	Medium brown	Mid brown with warmth	Medium brunette hair
#8	Ash brown	Light brown with a cooler tone	Light brown, dark blonde
#18	Ash blonde	Dark blonde with a cool, muted tone	Dark ash blonde hair
#27	Honey blonde	Warm golden or strawberry blonde	Warm blonde hair
#60	Platinum blonde	Very pale, cool, almost white blonde	Platinum or silver-blonde hair
#613	Bleach blonde	Very pale golden blonde	Light golden blonde hair

Anything lighter than about #4 has usually been lightened, because very little natural hair is that light. Ask the seller whether the shade you want is natural or colored.

Why is 1B the most popular shade?

#1B is the most popular extension shade because most natural black hair is not a true jet black. Undyed black hair usually shows a warm brown cast in sunlight, and #1B has that same cast. Pure #1 is best kept for hair that has been dyed black, which looks deeper and flatter.

What do mixed codes like 4/27 or 2/613 mean?

Mixed codes describe hair with more than one shade. The format varies by brand, but these are the usual meanings:

• A slash, such as 4/27, often means highlights: a base of #4 with streaks of #27.
• A T or an arrow, such as T2/613, usually means ombre: #2 at the top fading to #613 at the ends.
• An R prefix, such as R8/60, often means rooted: a darker root shade blending into the main color.

Because these vary so much, check the photos and ask if the description is not clear.

Which number is closest to your hair?

Your closest number is the one that matches the ends of your hair in daylight, not the roots. The ends are where extensions sit next to your own hair, and they are often lighter than the roots from sun and washing.

Three quick steps:

1. Stand by a window in daytime with no flash.
2. Hold a section of your hair from the lower half of your head.
3. Compare it with the shade chart and note the two closest numbers.

If you land between two shades, choose the darker one for dark hair and ask about blending two shades for highlighted hair. Our step-by-step guide to matching extensions to your hair color goes further, including how to photograph your hair so the color is accurate.

What about grey and salt-and-pepper hair?

Grey and salt-and-pepper hair does not fit the standard number scale because it mixes pigmented and white strands. It is usually described by the share of grey, such as around 30%, 50% or 80% grey. If your hair is grey or going grey, send us a photo and we will tell you what we can match.

Not sure which number is yours?

Numbers get you close, but only a side-by-side comparison confirms a match. Send us a photo of your hair taken in daylight through our contact page and we will reply with the shade we would choose. For more on picking the right piece, start with our beginner’s guide to at-home hair extensions.