Last updated: July 2026
SurfSizer works out the numbers people usually have to guess at — how many litres your next surfboard should be, what wetsuit thickness the water calls for, which wetsuit size you actually take, how long your leash needs to be, and which wax grade suits the temperature you surf in.
It was built around one idea: show the maths. Every calculator on this site prints the coefficients it used and the arithmetic it did, so you can check the answer by hand or disagree with it on informed grounds. No login, no sign-up, no email capture, no paywall.
Who runs this site
My name is Farasat Abbas Naqvi. I work as an engineer, and in my spare time I design websites and build practical online tools that make everyday tasks easier. You can read more about my professional background on LinkedIn, and see other things I have built at Store Front Studio.
Let me be straightforward about what I am not. I am not a shaper, I am not a sponsored surfer, and I would not ask you to take my word for anything on the strength of who I am. What I can offer instead is a tool that publishes its own method. Every ratio, every adjustment and every temperature band used on this site is printed on the page next to the result, along with where it comes from and where it stops being reliable. You should be able to audit the answer rather than trust it.
That is deliberate. Surf sizing is full of confident numbers presented without any explanation of how they were reached, and a figure you cannot check is not much use when you are about to spend several hundred on a board.
Why I built it
I built SurfSizer after looking at what was already out there and finding two recurring problems. Some sizing tools hand you a single number with no indication of how it was calculated, which makes it impossible to know whether it applies to you. Others are attached to a shop, which means the recommendation and the sales pitch come from the same place.
I wanted something plainer: put in your details, see the number, see exactly how it was reached, and then go and have a better conversation with a shaper or a shop. The calculators are the fastest route to an answer, and the guides around them explain the reasoning in more depth for anyone who wants it.
What is on the site
There are five working calculators:
- Surfboard volume calculator — litres from weight, ability, age, paddle fitness, wave type and construction.
- Wetsuit thickness guide — neoprene thickness from water temperature, adjusted for cold tolerance, session length and wind.
- Wetsuit size chart — your size across the major brands from height, weight and chest.
- Leash length calculator — length and cord thickness from board length and conditions.
- Wax grade tool — which wax your water temperature needs, and what to use as a basecoat.
Alongside them sit the explanatory guides: what size surfboard you need, the surfboard size chart, how to choose a surfboard, what to wear under a wetsuit, and surfboard fin types.
How I build and maintain it
I work on this site personally. I write the calculation logic, the guides and the interface, and I test the numbers against real boards and real published size charts rather than copying figures from other sites.
It is an ongoing project rather than something launched once and left alone. The most recent round of work added the leash length calculator and the wax grade tool, a full guide to fin setups, a grouped drop-down navigation so the tools are easier to find, and a back-to-top control on the longer pages. Two accessibility problems were found and fixed in the same pass — a colour contrast issue on the calculator panels, and a keyboard trap in the navigation.
Corrections are welcome and I would rather hear about a wrong number than not. If a chart on this site disagrees with a brand's own current sizing, or a calculator gives you something that does not match your experience on the water, tell me and I will look at it.
How to read the numbers here
Every figure on this site is an estimate with a sensible range around it, not a verdict. Surfboard volume in particular is a starting point for a conversation with a shaper — two surfers at identical weight and ability can be happy on boards several litres apart, and neither of them is wrong.
The wetsuit thickness recommendations are guidance for typical conditions and typical sessions. How you personally feel the cold matters more than any chart, and so does how long you stay in and whether it is blowing. Sizing charts vary between brands, and brands revise them; where the two disagree, the brand's own current chart wins.
Nothing here is safety advice. Conditions, your own ability on the day and local knowledge decide whether it is sensible to paddle out, and no calculator can tell you that. Brand names used on this site belong to their respective owners; SurfSizer is independent and not affiliated with, endorsed by or sponsored by any of them.
Approach to privacy
Everything on this site is calculated in your browser. Your weight, height, ability and every other input stay on your device — they are never transmitted anywhere, because there is nowhere for them to go. The calculators have no server behind them.
As it currently stands the site sets no cookies at all, runs no analytics, and loads nothing from third-party domains. There are no fonts, scripts or images fetched from anywhere other than surfsizer.com. If that ever changes I will say so here and put proper cookie controls in place first.
Get in touch
Questions, corrections, disagreements about a number, or a request for a calculator that does not exist yet — all genuinely welcome. Email hello@surfsizer.com.
SurfSizer is independently built and maintained by Farasat Abbas Naqvi. I hope it saves you from buying the wrong board.