Methodology · Model 1.0
How we estimate the rankings
Nobody publishes how many of each foundation, mascara or lipstick gets sold across every retailer. So the shares on Ask Bestie Beauty are estimates, built each month from the best sales figures we can get in each region. Every ranking says which sources it rests on.
Current coverage
The real dataset contains dated Sephora and Ulta US bestseller observations. Available categories are listed in the API and charts. It is updated by the weekly collection script. Missing months and categories are unavailable; prices are not invented. Retailer reuse permissions remain under review; this is an initial limited-coverage edition.
What the number means
"Est. 21.7% of purchases" next to a lipstick means that, of the lipsticks bought in that market that month, we estimate 21.7% were that one. It's a share of what people are buying now — not of what's sitting in everyone's makeup bag, and not a measure of quality.
Where the numbers come from
The estimate is built from purchase data: beauty-retailer bestseller lists, unit counts and shopper interest. It shows what people are actually buying, month by month.
| Source | Market | What we use | Status |
|---|---|---|---|
| Sephora US bestsellers | United States | Retailer category bestseller order, not measured unit sales or national market share | Waiting for access |
| Ulta bestsellers | United States | Retailer category bestseller order, not measured unit sales or national market share | Waiting for access |
| Cult Beauty bestsellers | uk | Category bestseller rankings | Planned |
| Douglas bestsellers | eu | Category bestseller rankings | Planned |
| Mecca bestsellers | au | Category bestseller rankings | Planned |
We only use data we're allowed to use. We don't scrape sites whose terms forbid it.
How a ranking is made
- Every list becomes a share. Unit counts and percentages are divided by the list's total. A bestseller list only gives an order, so position 1 counts for twice position 2 and three times position 3, and the whole list is taken to cover about 75% of the category's sales. Different shades of one product are added together.
- Lists are averaged with weights. Unit counts and shares count in full; a bestseller order counts 0.7 as much, because it says less. Some sources carry more weight than others.
- Each market leans on its own shops. For a market's ranking, its own retailers make up 80% of the weight and other markets 12%. If a group has no data, its share goes to the others.
- The global ranking weights markets by size. Markets are split by their rough share of beauty spending (United States 100%).
- One odd month can't swing it. Each month's figure is 70% the new data and 30% last month's estimate.
- Small shares are dropped. Anything under 0.5% is left out, and the rest is rounded to one decimal.
If a market has no purchase data of its own for a category yet, it shows the global ranking, and the ranking says so.
Confidence
- High: three or more sources including real unit counts or shares, or four or more sources of any kind.
- Medium: two sources, or one with real unit counts.
- Low: a single bestseller list.
What it isn't
It isn't a review or a skin-match. A product can be popular and wrong for your shade, skin type or budget, and the ranking only covers the products in our catalogue. Shares are rounded estimates; treat a gap of a point or two as a tie.