How to Measure a Knotted Dildo:Knots, Waists, and Length

1. Map the shape before measuring

Set the product down in its natural resting shape and identify the sections you want to record.

For your own measurement notes, number the knots from the tip toward the base: Knot 1, Knot 2, and so on. Label the narrower sections between them as Waist A, Waist B, and so on. If an existing product chart uses different labels, keep those labels when copying its specifications.

A knot is a raised bulge along the shaft. A waist is a narrower section between bulges. The head, knots, waists, and base are separate measurement locations.

Take a reference photograph with the labels placed beside the product. This photograph records where you measured; the photograph itself is not a substitute for the measurements.

For each location, the useful questions are:

• How wide is this section?
• What is its circumference?
• Where is it along the length?
• Which tool, orientation, and measuring path were used?

2. Prepare your tools and keep the shape relaxed

A ruler, a narrow flexible measuring tape or nonstretch string, and a notebook are enough to begin. Calipers can help record width if their jaws can touch the product without pressing into it.

Keep the product unstretched and unbent by hand. Support it so that its own weight does not noticeably flatten the section being measured.

Soft material changes shape under pressure. Bring the tool into light contact, record the reading, then remove and reposition it to check the result. Pulling a loop tighter or squeezing the calipers can produce a smaller number without describing the product’s resting shape.

Also record the model and size. “Small” on one design does not define the dimensions of another.

3. Measure the width of each knot

Find the widest cross-section within the individual knot you are measuring. Position the ruler or calipers across that section, rather than diagonally along the shaft.

On an oval or sculpted knot, width can change with orientation. Record two readings when useful:

• Side-to-side width: across the product from the chosen front view.
• Front-to-back depth: across the same section from the side.

Keep the reference orientation visible in your photograph or notes.

Use width or depth for these directional readings. A measurement taken across an irregular shape does not automatically establish a circular diameter.

Repeat the process for every knot. A width recorded at the largest knot does not describe the smaller ones.

4. Measure circumference at the same section

Circumference is the distance around a section. Keep it paired with the width reading taken at that location.

Place a narrow tape or nonstretch string around the selected section. Keep the loop level across the knot, without twisting or pulling it into the material. If using string, mark where it meets itself and measure that length against a ruler. A nonstretch-string method is also described in SquarePegToys’ circumference measuring guide.

On a sloping knot, watch for the loop slipping into a narrower waist. A tilted loop can also cross different parts of the bulge instead of staying at one section.

Let the loop rest against the outer contour without forcing it into recessed channels. Note that method if the surface has pronounced grooves or raised texture.

Do not replace a recorded circumference with π multiplied by a width reading. That calculation assumes a circular cross-section; sculpted knots may have a different outline.

5. Record waist measurements and knot positions

Measure each waist separately

Find the narrowest section between the neighboring knots. Record its width and circumference using the same orientation and contact pressure as before.

A waist measurement cannot be worked out by subtracting one knot measurement from another. It needs its own reading.

If the narrow section changes gradually rather than forming a clear minimum, identify the exact location in your reference photograph.

Add the tip-to-knot distance

Mark the section where you measured each knot. Then record its position from the tip using a stated path.

For a straight reference, place a ruler beside the resting product and read the position of the marked section along that ruler, starting from the tip. Label this as a straight-line tip-to-knot distance.

If you instead follow the curved surface with a flexible tape, label the result as a surface-path distance. Keep that path consistent for all the positions in the same record.

These two methods can produce different results. The label makes the number useful.

Define what you mean by knot spacing

The distance between two measured knot sections differs from the length of the narrow waist between the bulges.

For spacing, identify both endpoints and use the same measuring path. A note such as “Knot 1 measured section to Knot 2 measured section, straight-line reference” is more informative than an unexplained “knot gap.”

6. Keep total length and insertable length separate

Record total length and insertable length using the endpoints shown in the product’s specifications or measurement diagram.

A base-inclusive total length and a listed usable shaft length describe different parts of the product. Neither tells you where each knot sits.

On curved designs, state whether the length was measured in a straight line or along a surface curve. Do not pull the product straight to obtain a longer reading.

For the broader definitions of length, width, diameter, and circumference, see the Kervyra Size Guide.

7. Recorded knot measurements: Morrowknot and Neruvon

The product records below list knot diameter and circumference separately. They retain the specification labels used in those records.

For sculpted shapes, read the listed diameter alongside the recorded circumference rather than using one to calculate the other.

Source: existing Morrowknot and Neruvon records and product specifications, checked October 24, 2026. Centimeter values are the original records; inch values are approximate conversions rounded to two decimal places.

These figures describe the listed knots. The records used here do not provide complete waist measurements or tip-to-knot distances, so those dimensions remain unspecified.

When comparing products, check the location label as carefully as the number. A larger-knot measurement and a first-knot measurement may refer to different parts of two designs.

8. Keep a measurement record someone else can follow

A useful record includes more than a row of numbers.

If a second reading differs, check the section, orientation, loop angle, and pressure before changing the record. Do not average measurements taken at different locations or along different paths.

If you are measuring a product you already own to compare with a new one, use corresponding locations and methods wherever possible. Keep the two records separate when their definitions differ.