Methodology and sources

Every figure on this site comes from a brand's own published size chart, specification sheet or sizing article, read on 2026-10-20. The site applies those charts to a height, weight or trip length; it never estimates a figure a brand did not print. Where brands disagree, it shows the range across them and, when they share one, the window they all agree on.

Sources

Kayak specifications are read per model from each product page; the links are in the kayak table. Bike charts marked "published by evo" are the brand's chart as the retailer evo reproduces it.

Method, by category

Skis

Each chart is read at the row that matches the rider's height. When a height falls between two printed rows, both rows are read and the answer spans the lower row's low value to the upper row's high value. Nothing is interpolated. Ability mapping: evo's beginner, intermediate and expert columns; K2's beginner and intermediate ranges, and for advanced the span from its "advanced / playful" low to its "advanced / charger" high; Faction's single range for every ability.

Snowboards

Length: every row whose printed weight range contains the rider's weight is read (Jones, Never Summer, evo), and the answer spans those rows. A height-based row (evo, Never Summer) is used in the calculator when height is given. Open-ended rows (165+, 160+, 158+) give a floor, not a ceiling. Width: the boot size is read against Jones's minimum waist width table, Never Summer's width classes and Burton's three boot-size tiers.

Kayaks

Load = paddler weight + gear. Three published rules size the rated (maximum) capacity a kayak needs for that load: Brooklyn Kayak Company's 70% performance rule (capacity at least load ÷ 0.70), Kokopelli's 25-50% rule (capacity 1.25 to 1.5 times body weight), and Old Town's own per-model usable capacity (usable capacity at least the load). Each model's published figures are then checked against the load. Formulas: BKC capacity needed = load ÷ 0.7; Kokopelli capacity = body weight × 1.25 to 1.5.

Paddleboards

Volume: iRocker's rule (body weight in kg × 2.2 to 2.5) and Alpkit's rule (total weight in lb × 1.1 to 1.4 for beginners, × 0.9 to 1.1 for experienced paddlers) are both applied; where they disagree the answer shows the span. Length, width and thickness: iRocker's chart by weight band. Boards: each brand's published rider maximum is compared with the load, and iRocker's advice to stay 10-15% under the stated maximum is shown as a margin. Kilograms = pounds ÷ 2.20462.

Bikes

Each chart lists a rider-height span per frame size. A height that sits inside two spans (charts overlap at the edges) returns both sizes, as the brands do. Heights are compared in inches.

Backpacks

Each brand's trip-length guidance is read for the number of nights. Gregory states nights; Gossamer Gear states days, read as nights + 1; Osprey's statements for a single overnight, a three-day trip and more than a week are used where they apply, with Osprey's trip-length categories shown alongside. The answer spans every brand that covers the trip.

What was left out, and why

• evo snowboard waist-width-by-boot-size table: The table's columns did not line up when fetched (two reads mapped men's and women's sizes differently), so it is left out rather than guessed.
• Burton board length chart: Burton publishes length charts per board model only (https://www.burton.com/en-us/pages/size-charts); there is no general weight-to-length chart to quote. Burton's wide-board rule is used.
• Perception kayaks: perceptionkayaks.com disallows automated reading, and the Perception specification tab on confluenceoutdoor.com loads by script, so no capacity figure could be read from the brand. Perception models are left out until they can be.
• Old Town Twin Heron: The product page prints a usable capacity of 437 lb next to 128 kg, which do not match; left out until the page is corrected.
• Trek size charts: trekbikes.com size-chart pages could not be read (the road buyer's guide points to a script-driven Size Finder with no printed table), and dealer reproductions do not credit Trek. Trek is left out until its chart can be read from Trek.
• Specialized Sirrus: The Sirrus fit page prints rider-height bands without the size column.
• Cannondale and Canyon: Cannondale's guides give a stand-over method but no height table; Canyon's guide gives only an overall height span per bike category.
• REI pack capacity table: The REI page could not be fetched; REI is a retailer and its guidance is not needed for the brand range.

Gaps

• Pages cover the heights, weights and trip lengths most charts print; outside a chart's printed rows that brand is simply absent from the answer.
• Burton publishes snowboard length charts per model only, so only its width rule is used.
• Paddleboard volume rules are general; a board's own rider maximum always wins.
• Kids' gear is not covered beyond the smallest rows the adult charts print.

Refresh

Size charts change with model years. Each data file is re-read from its source before each winter (snow) and each spring (water and bikes), and the checked date updates. Corrections: hello@gearfitatlas.com. Data version 2026-10-20.