SurfCalc is a calculator and a catalog. It has no accounts and asks for nothing about you beyond what you type into the calculator, which stays in your browser.
The weight, skill and conditions you enter are used in your browser to compute a volume. They are never sent to SurfCalc. A few small preferences (your weight unit, your country and "near a shop" choice in the finder and, on phones, whether the filter panel is open) are stored in your browser's local storage so they survive a reload. If you press the location button in the finder, your browser asks you for permission and the position stays on your device; SurfCalc only uses it to measure the distance to each shop. Clear your browser data to remove them.
SurfCalc uses Google Analytics 4 to count visits, see which pages and filters are used, and which stores people click through to. IP addresses are anonymised, no advertising features are enabled, and the data is not combined with anything that identifies you. Google's own notice describes how it processes this data: How Google uses information from sites that use its services. If your browser sends a Do Not Track or Global Privacy Control signal, or you use a content blocker, the tag is simply not loaded.
Listings link to the brand or shop that sells the product. When you follow one, the link passes through surfcalc.app/go.php, which records the store, the product, the time, the SurfCalc page you came from, and a visitor id made by hashing your address and browser with the day's date, so we can count how many people we send to each store without keeping addresses. The store then sees SurfCalc as the referring site. Some of those links carry a referral code, and if you buy after following one the store may pay SurfCalc a commission at no extra cost to you. As an Amazon Associate, SurfCalc earns from qualifying purchases. Commissions never affect how products are ranked: the finder sorts by how close a board's volume is to your number, or by whatever column you choose. The one exception is the item labeled Featured above a tab's results, which is picked from an affiliate store's listings that match your filters and is marked as such; the table under it is unchanged.
The catalog is built from the public product feeds that stores publish. It contains product names, dimensions, prices, stock status and photos, refreshed nightly. It contains no customer information from any store.
SurfCalc sets no cookies of its own. Google Analytics sets its _ga cookies to tell one visit from the next; see the Analytics section above.
Last updated 18 October 2026.