HMHairMetric
METHODOLOGY

How the estimate is built.

HairMetric is a planning estimator. It is not intended to replace a braider who has assessed your actual hair, parting plan and technique.

1. Start with a braid-size and length baseline

The first model uses published knotless-braid quantity ranges as a starting point. Those ranges are normalized into 100-gram-equivalent packs so recommendations can be compared across brands.

2. Convert the estimate into grams

Pack counts are inconsistent because one brand may sell 52 grams while another sells 100 grams or more. HairMetric therefore treats grams as the primary quantity and converts to packs only at the end.

3. Adjust conservatively for head circumference

The model uses 22.25 inches as its neutral reference point and applies a limited adjustment above or below that value. The adjustment is intentionally capped so a slightly larger head does not unrealistically double the estimate.

4. Apply smaller density and fullness modifiers

Natural density and desired finished fullness matter, but braider technique matters too. For that reason, these inputs change the result less than braid size or finished length.

5. Convert grams into the pack weight you entered

If the estimate is 700 grams and your chosen product contains 100 grams per pack, the calculator returns seven packs before the backup recommendation.

Version 1 limitation: this model is calibrated for knotless braids using synthetic/pre-stretched extension hair. Boho human hair, feed-in styles, twists and other installations should use separate models.

Boho / goddess human-hair model

The boho calculator estimates only the loose human-hair curl portion. It anchors a balanced, medium, mid-back install around published 2–4 bundle / 200–400g guidance, then adjusts by braid count, finished length, head size and curl fullness. Because stylist placement technique varies substantially, the result is intentionally shown as a range rather than a single precise number.

Source material

How this gets better

The strongest future calibration data will come from real installs: style, braid size, finished length, head circumference, natural density, total grams purchased, and total grams actually used. HairMetric can use that information to tighten ranges over time.

NATURAL-HAIR CONTRIBUTION

Density and strand thickness are treated separately

HairMetric does not assume that higher natural-hair density automatically means more extension hair is needed. Density describes how much natural hair is growing across the scalp, while individual strand thickness describes whether each hair is fine, medium or coarse.

For the same target braid size, a part containing more natural-hair bulk may need slightly less extension hair to reach the desired finished thickness. A part containing less natural-hair bulk may need slightly more. HairMetric therefore uses density and individual strand thickness to make a modest adjustment to the extension-hair estimate and feed-in starting point.

Curl pattern is not currently used as a major gram-weight adjustment. It can matter for grip, stretching, blending and technique, but HairMetric avoids treating visual curl categories as a direct substitute for strand thickness or density.