+ How to Tie a Prusik Knot — Step-by-Step Climbing Knot Guide | BoulderingList
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Prusik Knot

intermediate

The Prusik knot is a friction hitch — a thin cord wrapped around a thicker rope that grips when loaded and slides when unloaded. Foundation of self-rescue and rope ascent.

When to Use

A friction hitch tied with a thin cord around a thicker rope — slides freely when unloaded but grips tight when loaded. Used for ascending ropes, self-rescue, and anchor extension.

The Prusik knot (named after Austrian climber Karl Prusik who invented it in 1931) is the foundational friction hitch in climbing. A thin loop of cord (typically 6mm or 7mm accessory cord) is wrapped around a thicker climbing rope. When the cord is unloaded, it slides freely along the rope. When the cord is loaded perpendicular to the rope, the wraps tighten and grip the rope — sometimes well enough to hold body weight.

Prusik knots have many uses in climbing: ascending a rope (Prusiking), self-rescue from a dangling fall, backing up a rappel for safety, extending anchors, hauling loads, and many other applications. The skill is one of the most-taught in advanced climbing courses because it underpins so many self-rescue techniques.

For a Prusik to grip reliably, the cord should be 60-70 percent of the diameter of the host rope. Too thin and it cinches into the rope and is hard to release; too thick and it slips. 6-7mm cord on a 9-10mm climbing rope is the typical combination. Many alternative friction hitches exist (Klemheist, Autoblock, Bachmann, Valdotain Tresse) — each with slightly different properties.

How to Tie the Prusik Knot

  1. Step 1

    Take a closed loop of accessory cord (a "Prusik loop"), pre-tied with a double fisherman's knot. The loop should be roughly 60-90 cm in circumference.

  2. Step 2

    Wrap the loop around the host climbing rope, threading the bottom of the loop through the top of the loop. This is the first wrap.

  3. Step 3

    Wrap the loop around the rope two more times, threading through the same way each time. The cord should sit in three even wraps around the rope.

  4. Step 4

    Dress the wraps so they sit cleanly side-by-side around the rope. Twisted wraps reduce grip.

  5. Step 5

    Pull on the loop to test the grip. The knot should hold body weight when loaded perpendicular to the rope, and slide freely when not loaded.

Tips for Tying It Well

  • Always pre-tie your Prusik loops at home with a double fisherman's knot. Tying knots in cord while hanging is awkward and error-prone.
  • The cord-to-rope diameter ratio matters. Aim for cord 60-70% of host rope diameter (e.g. 6mm cord on 9mm rope).
  • Practice the Prusik on flat ground first. Get the muscle memory before relying on it in a real situation.
  • Test the grip before committing weight. A poorly-dressed Prusik can slip.

Common Mistakes

  • Wrong diameter cord. Too thin cord cinches in and is hard to release; too thick cord slips.
  • Twisted wraps. The wraps must sit cleanly side-by-side to grip properly.
  • Loading the Prusik in the wrong direction. The loop must be pulled perpendicular to the host rope to grip; pulling parallel to the rope makes it slide.

Related Knots

Double Fisherman's Knot

intermediate

The double fisherman's knot is the climbing standard for joining two ropes. Two double-overhand knots tied around each other create a low-profile, bombproof join.

Overhand Knot

beginner

The overhand knot is the simplest knot — a single loop with the working end passed through. Used as a stopper, a backup, and the foundation for more complex knots.

Clove Hitch

beginner

The clove hitch is a fast adjustable hitch that attaches a rope to a carabiner or post. Climbers use it to clip into anchors at belay stations.

Take it further

Browse the full climbing knots library, or find a climbing gym to practice tying knots in real climbing situations.

All Climbing Knots Find a Gym Beginner's Guide

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