Rope & Knot Calculators
Free, practical tools for ropework — estimate the rope you need, find the right knot for the job, understand working load limits, plan a paracord project, and get your splice or whipping right the first time.
Rope Length Estimator
Add up the run length, a per-knot allowance, and a waste margin across however many pieces you need, to see exactly how much rope to buy
Knot Selector
Pick your use case — sailing, decorative and Chinese knotting, fishing, general utility, or camping — and get a short list of knots that fit
Working Load Limit Guide
General guidance, not a safety certification. Divide a rope's rated breaking strength by a design factor, with an optional derating for a knot or splice
Paracord Needed Calculator
Work out how much 550 paracord a Cobra, King Cobra, or Fishtail bracelet or lanyard needs from the finished length and weave
Splice Tuck Counter
Get a recommended tuck count for a 3-strand eye splice, or the bury length for double-braid, plus the extra rope it will consume
Whipping Length Calculator
See how many wraps and how much twine it takes to whip a rope end, worked from the rope's own circumference
Working Load Reference
A sensitivity table for the Working Load Limit Guide's own math — see how much the result moves across common knot/splice efficiencies and design factors