Surfboard fin size chart: what size fins do you need?
Fins are sized by your body weight, not your board. Enter yours to find your size, then learn how setups and templates change the way your board feels.
By SurfSpotGuide EditorialPublished June 24, 2026
Find your fin size
Enter your weight to see the fin size for you.
Fin Size by Rider Weight
FCS II sizes its fins into weight brackets, and other brands do much the same with slightly different ranges, so check the chart for the fins you buy. These ranges overlap on purpose: pick the smaller size if you want a looser, more playful board, and the larger size if you want more hold and drive.
| Size | Weight (kg) | Weight (lb) | Notes |
|---|---|---|---|
| XS | Under 55 kg | Under 120 lb | Groms and very light surfers |
| S | 48–70 kg | 105–155 lb | Lighter surfers; looser, skatey feel |
| M | 65–88 kg | 145–195 lb | The most common size — balanced all-rounder |
| L | 75 kg+ | 165 lb+ | More hold and drive for heavier surfers |
| XL | 86 kg+ | 190 lb+ | Maximum hold and projection |
The chart gave you a number. Here’s what it can’t tell you.
A chart is good at exactly one thing: the number. It won’t tell you that most surf schools hand you the board, the wetsuit and the leash with the lesson — so the gear you just looked up may not be the first thing you need to buy at all. The free Beginner’s Surf Guide covers the rest:
- What your school already provides, and the short list worth packing yourself
- The five questions to ask before you book — and the red flags hiding in the answers
- How lesson one actually runs, from dry-sand pop-ups to your first green wave
- The lineup rules nobody explains until you’ve broken one
No spam · Instant delivery · Unsubscribe anytime
Fin Setups Explained
- Single fin1 finSmooth, drawn-out turns. Classic longboard and retro feel.
- Twin2 finsFast, loose, and playful in small waves. No center fin.
- 2 + 13 (1 large center + 2 side) finsLongboard standard — stability with some manoeuvrability.
- Thruster3 (equal) finsThe all-round shortboard standard. Drive, control, and release.
- Quad4 finsSpeed and a loose feel down the line. No center fin.
- 5-fin5 boxes finsNot ridden with all five — lets you switch between thruster and quad.
What Fin Shape Changes
Once you have the right size, the fin's template (its shape) fine-tunes how the board rides. These four measurements do most of the work:
- BaseLonger base = more drive and acceleration. Shorter base = tighter, snappier turns.
- DepthDeeper fins = more hold and grip. Shallower = looser, easier to slide.
- Rake / sweepMore rake = longer, drawn-out turns. Less rake = pivot-y, responsive turns.
- FlexStiffer fins = responsive and reactive. More flex = forgiving with spring out of turns.
Rule of thumb: start with the correct size for your weight and a neutral, all-round template. Only experiment with base, rake, and flex once you can feel what your current fins do well and poorly.
Fins in your size
All-round sets that match the sizing above, plus a cheap spare.
We may earn a small commission if you buy through links on this page, at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. We only recommend gear we'd ride ourselves.
FCS II Performer Neo Glass Fins
FCS · Amazon
The all-round default — balanced drive and release that suits most beginner-to-intermediate boards.
Futures F6 Thermotech Fins
Futures · Amazon
Affordable, forgiving thruster set for the Futures fin boxes on many soft-tops and funboards.
Dorsal Signature Thruster Fins
Dorsal · Amazon
Budget replacement set — a cheap way to get a spare or replace lost soft-top fins.
Related guides
Frequently asked questions
How do I choose the right fin size?
Fin size is chosen primarily by rider weight. Brands group fins into brackets (XS, S, M, L, XL) keyed to weight ranges. A 65–88 kg (145–195 lb) surfer takes a Medium. Heavier surfers need larger fins for hold and drive; lighter surfers need smaller fins so the board stays loose and easy to turn.
Are FCS and Futures fins interchangeable?
No. FCS and Futures use different fin boxes and base shapes, so they are not cross-compatible. FCS II also differs from the original FCS. Check which box your board has before buying. Brands bracket fins by weight in much the same way, but their exact ranges differ, so check the chart for the fins you buy.
What’s the difference between a thruster and a quad?
A thruster (three fins) is the all-round standard — balanced drive, control, and release. A quad (four fins) has no center fin, giving more speed down the line and a looser feel that many surfers prefer. Many modern boards are 5-fin so you can run either setup.
Does fin size matter for beginners?
Most beginners on a soft-top should just run the fins that came with the board. Once you move to a hard board, sizing to your weight gives noticeably better hold and paddling. If in doubt, beginners benefit from slightly larger fins for the extra stability.
What fins do I need for a bigger surfer?
Surfers over 90 kg (200 lb) should run Large or XL fins. Undersized fins on a heavy surfer feel skittish and slide out in turns because there isn’t enough surface area to hold the rail in the wave face.
Dial in your whole setup
Fins are just one piece. Make sure your board volume and dimensions match you too — start with the size chart.
More Surf Guides
The chart gave you a number. Here’s what it can’t tell you.
A chart is good at exactly one thing: the number. It won’t tell you that most surf schools hand you the board, the wetsuit and the leash with the lesson — so the gear you just looked up may not be the first thing you need to buy at all. The free Beginner’s Surf Guide covers the rest:
- What your school already provides, and the short list worth packing yourself
- The five questions to ask before you book — and the red flags hiding in the answers
- How lesson one actually runs, from dry-sand pop-ups to your first green wave
- The lineup rules nobody explains until you’ve broken one
No spam · Instant delivery · Unsubscribe anytime