PaddleSizer

Tools

Sizing calculators

Updated 2026-09-24. Researched from published specifications, capacity ratings and verified owner reviews, not hands-on testing.

Quick answerStart with the paddle board size calculator or the kayak weight capacity calculator: they decide which boat or board fits you. Then size the paddle and the life jacket.

Paddle board size calculator

Enter your weight, height, skill and how you will paddle. Get the board volume in litres, the width and length to shop for, and the rated capacity to look for.

Kayak weight capacity calculator

Add up paddler, passenger and day gear, then apply the 70 percent performance rule to find the rated capacity your recreational kayak needs.

Kayak size calculator

Pick the kayak length and style that fits your height, weight and water. Legroom, stability and tracking all change with length.

Kayak paddle length calculator

Kayak paddle length depends on boat width first and your height second. Add seat height for raised sit-on-top seats and choose low or high angle.

SUP paddle length calculator

A stand up paddle should be 8 to 10 inches taller than you for all-round paddling. Touring, surf and board thickness shift that number.

Life jacket (PFD) size calculator

Children size by weight into USCG classes, adults size by chest. Enter the paddler and get the class, the size and the fit check.

Roof rack load calculator

Add up kayaks or boards, the carriers and the crossbars, then check the total against your car's dynamic roof load and the rack rating.

Inflation PSI and pump time calculator

How many pump strokes and minutes it takes to inflate a paddle board or drop-stitch kayak floor to its target PSI, and how much the pressure climbs in hot sun.

Kid or toddler passenger check

Before a child rides on your paddle board or in your kayak: check the combined load against the 70 percent rule, the life jacket class they need and whether they are ready for their own board.

Most-bought boats and boards

This is researched general information, not professional advice. Sizing figures are starting points: confirm against the maker's own sizing chart and the capacity printed on the boat or board.