Cordelette Length Calculator

Cordelette Length Calculator

Estimate the cut length for a climbing cordelette from anchor span, master point drop, knot choice, tie-in style, cord material, diameter, tails, and reserve cord.

🧗Cordelette Anchor Presets

Anchor Span, Knot, Tie-In, and Cord Inputs

Metric entries convert internally for the same result.
Use 2 to 5 pieces, bolts, trees, horns, or screws.
Horizontal distance between the farthest anchor points.
Vertical reach from anchor line to master point.
Add cord for staggered placements or ledge geometry.
Tree, horn, bollard, or large block wraps add girth.
Use zero when no object wraps are used.
Different knots consume different amounts of cord.
Tie-in style changes loop allowance and knot count.
Material affects stretch allowance and knot care.
Common climbing cordelette sizes run about 5.5 to 7 mm.
Visible tails give margin after dressing and loading knots.
Reserve covers real rock shape and imperfect dressing.
Compare the estimate with cord already on your rack.

This calculator estimates cord geometry only. Climbing anchors require trained judgment, rated equipment, sound placements, and partner checks.

Recommended Cut
24.0
ft of cord
Usable Loop
10.8
ft after knots and tails
Knot And Tail Use
2.4
ft consumed
Stock Margin
OK
available cord comparison
Anchor geometry allowance0 ft
Object wrap allowance0 ft
Knot allowance0 ft
Tail allowance0 ft
Material and diameter adjustment0 ft
Reserve added0 ft
Nearest common store cut0 ft

📏Cord Material and Spec Grid

6-7 mm
Nylon cord range
5.5-6 mm
Aramid cord range
6 in
Practical minimum tail
20-24 ft
Common trad cordelette

🧵Cord Material Notes

Nylon accessory cord

forgiving

Good knot behavior and some stretch. Bulkier at 7 mm, but familiar for everyday anchors.

Aramid cord

compact

High heat resistance and low stretch. Knots need careful dressing and inspection.

Dyneema blend cord

low stretch

Light and strong by rating, but slippery bends and knots demand extra care.

Polyester static cord

stable

Moderate handling with lower water absorption. Check device and knot compatibility.

📊Cordelette Length Tables

Anchor typeSpanDropCut length
Two close bolts2-4 ft1-2 ft14-18 ft
Compact 3-piece trad3-5 ft2-3 ft18-22 ft
Wide 3-piece trad6-9 ft2-4 ft24-28 ft
Tree or horn anchor6-10 ft2-4 ft26-32 ft
Four-point stance7-12 ft3-5 ft28-36 ft
Knot typeAllowanceBest useNote
Double fisherman's16-24 inClosed loopSecure, compact bend
Flat overhand bend12-18 inRetrievable cordNeeds long tails
Overhand master8-12 inCordelette masterFast and bulky
Figure-eight master12-18 inTraining anchorsEasy to inspect
Triple fisherman's20-30 inSmall slick cordConsumes more cord
Cut lengthApprox loopCompact reachWide reach
16 ft7-7.5 ft2-bolt anchorslimited
20 ft9-9.5 ft3-piece anchorsmoderate
24 ft11-11.5 ftstandard tradgood
28 ft13-13.5 ftlarge anchorsstrong
32 ft15-15.5 ftrescue riggingstrong
MaterialDiameterHandlingAdjustment
Nylon6-7 mmeasy knotsstandard
Aramid5.5-6 mmstiff+5%
Dyneema blend5-6 mmslick+8%
Polyester static6-7 mmfirm+3%
Small cordunder 6 mmtiny knots+6 in tails

💡Cordelette Calculation Tips

Measure the real anchor shape: The widest piece-to-piece span and the drop to the master point matter more than the number printed on old rack notes.
Budget for knots before cutting: Small, stiff, or slick cord can need more tail and knot allowance than soft nylon cord of the same finished loop size.

Calculating the correct length for a cordelette is an important task for a climber. If the cordelette is too short, it wont be able to reach the master point. Similarly, if the cordelette is too long, it can create excessive sag in the anchor system.

The cordelette should create a loop that allow for the equalization of the chosen anchor pieces, but it should not waste cord or create excess sag in the cordelette. Several variables will determine the length of the cordelette that is require to establish a secure anchor system. These variables includes the length of the span of the anchor system, the vertical drop distance, the type of knot that will be used, and the diameter of the cordelette.

How to Find the Right Cordelette Length

The geometric shape of the chosen anchor system will have an impact on the length of the cordelette that is required. For example, if two bolts are use in an anchor system, and those bolts are close together, less cordelette will be required than if three different anchor pieces are to be utilized. The length of the span between the anchor pieces is a critical measurement of the anchor system.

The length of the span of the anchor pieces and the vertical drop distance will determine the amount of cord that is require to create the loop. The vertical drop is the distance between the anchor pieces to the master point that will be used to lower the climber into the area that is to be climbed. The types of knots that are to be used in the cordelette can also impact the length of the cordelette that is required.

For instance, a double fisherman’s bend will require more cordelette than a flat overhand knot. Furthermore, the type of cord will also impact the amount of cordelette that are consumed by the knot. If the cordelette is made of a stiff material, it will consume more cord than if the cord is slickly.

Ensuring that the type of knot is chosen will allow the calculation of the cordelette to account for the amount of cord that the knot will consume. Additionally, the tails of the knots must also be accounted for. The tails of knots should be at least six or seven inches in length to ensure they dont roll underneath the load of the anchor system.

A calculator can be used to ensure that the length of the tails is build into the length of the cordelette that is to be cut. The material out of which the cordelette is made will also impact the length of the cordelette. For instance, nylon is an easy material to inspect for damage but will stretch and absorb water.

Aramid and Dyneema materials will not stretch and will withstand heat but may be less forgiving in the event that the cordelette is not tied with care. The diameter of the cordelette must also be accounted for in the equation. Thinner cordelette will require longer tails so that it is secure when tied.

The diameter of the cordelette must be accounted for in the calculation to ensure the amount of cord that are consumed by the knots is calculated correctly. The circumference of the object that the cordelette will be wrapped around will also impact the length of the cordelette. If the cordelette is to be wrapped around an object such as a tree, the circumference of that object will require that some of the length of the cordelette be consume by the circumference of that object.

Furthermore, the number of times that the cordelette will be wrapped around that object will also impact the required length of the cordelette. The average circumference of the object that the cordelette will be wrapped around can be measured. Furthermore, the number of times that the cordelette will be wrapped around that object can be determined.

This information can be accounted for in the calculation that determines the length of the cordelette. The evenness of the placement of the anchor pieces will also have some impact on the length of the cordelette. The placement of bolts that are offset from one another on overhang walls will require more cordelette to account for the difference between these two bolts.

Finally, it is also wise to include a percentage of reserve cord in the cordelette that is calculated. The reserve percentage of the cordelette will account for the difference between the length of the cordelette that is calculated and the length that is actualy use once the cordelette is dressed. A ten percent reserve in the length of the cordelette is commonly used.

Using a reserve percentage less than ten percent may cause the cordelette to be too short to effectively reach the master point when the cordelette is under load. Finally, the calculated length of the cordelette should be compared with the length of the cord that a climber has in their gear. Most cordelette cord comes in standard lengths.

A calculator can be used to determine the length of the cordelette that should be purchased to account for the length calculations. The length of the cordelette should be checked against the length of the cord that is already on a rack in the climber’s gear to ensure that it will not be cut to a length that is too short for other anchor points that can also be utilized in the future. The goal of calculating the length of the cordelette is to create a loop that will effectively reach the master point, allow for the even equalization of the anchors pieces, and allow for enough tail to the cordelette to inspect for damage.

Cordelette Length Calculator

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