Policy
AI notice
A machine-learning model is used here for exactly one job, and it is a narrow one. This page sets out what it does, what it is deliberately not allowed to do, the table that every number on this site actually comes from, and the limits the output has to be read against.
Last updated 5 September 2026
1What the service calculates
This service calculates the cost per wear of a garment: the price you enter, divided by an estimated number of wears derived from four properties — fibre composition, whether the heel and toe are reinforced, how the toe seam is finished, and how tightly the fabric is knitted.
It also works out the wear at which a dearer option breaks even on cumulative spend, and the cost per wear you would actually realise over a stated ownership horizon at a wearing frequency you choose. Those two are different questions and they can give different answers; both are shown.
2What the model does, and does not do
The model is used to identify, from your photographs:
- which fibres are present and in what proportions, read from the composition label;
- whether a reinforced panel is knitted into the heel and toe;
- whether the toe seam is flat and linked, or a raised overlocked ridge;
- roughly how fine or coarse the knit is.
The model does not produce a single number on this site
It does not estimate a number of wears and it does not calculate any monetary figure. Both of those are worked out in your own browser, from the coefficient table published below in full, using the price you typed. You can read the table, check the arithmetic and reproduce every figure by hand.
Model output can be wrong. It can misread a worn label, misjudge a gauge from an out-of-focus photograph, or miss a reinforced panel knitted in the same colour as the rest of the sock. Everything it reports is shown to you before it is used, and you can correct any of it.
3The coefficient table, in full
These are working estimates for the category, not measurements of any particular product. Every entry is a range, which is why every result is one too.
Base wears by fibre · wears, plain medium-gauge sock
- Combed / long-staple cotton60–110
- Longer fibres are held in the yarn along more of their length, so fewer ends work loose and the surface thins more slowly.
- Cotton (standard, carded)35–65
- Short fibre ends work out of the yarn under abrasion. This is what pilling and thinning look like early on.
- Merino wool70–130
- Crimped fibres recover their shape after compression, so the fabric keeps its thickness for longer.
- Wool (non-merino)55–100
- Resilient under compression, though coarser grades felt more readily in a hot wash.
- Polyamide / nylon130–220
- The most abrasion-resistant fibre commonly knitted into socks. Usually present in small proportions at the heel and toe.
- Polyester100–170
- Highly abrasion-resistant and dimensionally stable, though it holds odour more readily, which can retire a sock before it wears out.
- Acrylic40–80
- Reasonable abrasion resistance, but the surface pills quickly, which often ends a sock's life on appearance rather than on failure.
- Viscose / bamboo / modal30–60
- Weak when wet, and socks spend a great deal of time damp.
- Linen45–85
- Strong fibre, but stiff, and it abrades where it creases.
- Silk25–50
- Fine and smooth, with very little tolerance for repeated abrasion at the heel.
- Elastane / spandexstructural
- Sets the fit rather than the life. Above about 8% the sock usually loses its grip before the fabric wears through, and a slack sock slides and abrades faster.
A blend is weighted by its proportions. Elastane and similar structural fibres are taken out of the weighting and handled separately, because they set the fit rather than the abrasion life.
Reinforcement · multiplier
- Reinforced heel and toe1.30–1.55×
- Extra yarn is knitted into the two places that fail first. This is the single largest structural difference between two otherwise identical socks.
- No reinforcement1.00×
- The heel and toe carry the same fabric as the leg, and they take almost all of the abrasion.
Toe seam · multiplier
- Flat, linked toe1.10–1.25×
- The seam sits level with the fabric, so there is no ridge standing proud inside the shoe to concentrate abrasion.
- Raised, overlocked toe0.90–1.00×
- A ridge of stitching stands above the fabric surface and is rubbed by the shoe on every step. It is a wear starting point built into the sock.
- Toe seam not visible0.95–1.15×
- Without a photograph of the toe this is unknown, which widens the range in both directions.
Knit density · multiplier
- Fine gauge, dense1.15–1.35×
- More stitches carry the same load, so each one is stressed less and gaps open more slowly.
- Medium gauge1.00×
- The ordinary case, and the baseline these figures are built on.
- Coarse gauge, open0.75–0.92×
- Fewer, larger loops. Each one takes more load, and there is more open space for a hole to start in.
Conditions you tell us about · multiplier
- Tumble dried0.62–0.80×
- Heat and mechanical agitation together are the fastest way to shorten a sock's life. This is the single biggest thing in the user's own control.
- Washed above 40 °C0.78–0.92×
- Hot water accelerates fibre damage and, in wool, felting.
- Worn in work boots or heavily abrasive footwear0.50–0.70×
- The inside of the shoe does more damage than the sock's own construction does.
4The wear count is an estimate
An estimate, not a promise
The number of wears this service gives you is an estimate. It is not a promise, a warranty or a prediction about your particular pair.
These change the result materially, and none of them is knowable from a photograph:
- how you launder the garment, and tumble drying most of all — heat and mechanical agitation together are the fastest way to shorten a sock's life;
- how hard you wear it, which is not the same for a desk day and a twelve-hour shift;
- the state of your shoes, since a worn insole or a rough internal seam will out-abrade anything the sock's construction can resist; and
- whether the pair is lost, shrunk or retired on looks before it ever wears through — which is how most socks actually end.
For that reason every figure — the wear count, the cost per wear, and the realised cost per wear — is given as a range. There is no single number anywhere on this site presented as an exact answer.
5The dearer option is not always better
Read this before acting on any comparison
The more expensive option is not always the better value.
Where wearing frequency is low, where the risk of losing a pair is high, or where conditions are severe enough that nothing lasts, the cheaper option may remain the better buy — and the service will say so explicitly, with your own figures, in every comparison it produces.
That list is generated for every comparison, is shown on every plan including the free one, and is never covered by a watermark or placed behind a payment. A tool that reliably pointed at the expensive option would be a shop assistant; this is not one.
6No price information whatsoever
This service holds no price data
It does not look up, store or suggest any market price. It offers no price comparison and no purchasing route — no retailer, no availability, no link to buy anything, and no judgement about whether a price is reasonable.
The prices used come entirely from you. You tell us what they cost. We only work out how far that money goes.
No market price is stored in the database at any point. The only prices recorded are the ones you typed, kept against your own comparisons, and they are never aggregated, published or sold.
7No brand evaluation, no recommendation
This service evaluates no brand and gives no purchasing recommendation. It offers a comparison, from which you decide.
Any name read off a label is redacted before it can be displayed, exported, shared or drawn into an image. The redaction works from a closed vocabulary of textile and care terms; anything outside that vocabulary is replaced with a block.
8Not advice of any kind
This service provides no investment or financial advice, and no tax, legal or other regulated advice. It is a calculator, and the decision it informs is entirely yours.
9Prohibited high-risk uses
Output from this service must not be relied on for any of the following. It is not fit for any of them:
- medical purposes or any decision affecting health;
- legal purposes or any decision affecting legal rights;
- financial purposes, including investment, lending, insurance and valuation;
- safety-critical purposes of any kind;
- employment decisions;
- credit decisions;
- housing decisions; and
- judicial or law-enforcement decisions.
These are repeated, with the rest of the conduct rules, in the acceptable use policy.
10Your content and model training
Photographs, prices and comparisons you supply are not used to train, fine-tune, evaluate or benchmark any model, ours or a third party’s. Photographs are sent to a model provider only for property identification, under terms that prohibit retention and training, and are deleted from our systems within 30 days or immediately when you delete the comparison. The full retention schedule is in the privacy policy.