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intermediate

Prusik Knot

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.

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

Tying 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

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.
Watch out

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

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 Knots Find a Gym → Beginner's Guide

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