dD Calculator

In order to use the dD calculator, you need reference sizes.

You need a lace pricking and a yarn thickness for this pricking. If you then want to enlarge or reduce the pricking, or you are searching a new pricking size for a different yarn, this calculator will help you. Search for the appropriate dD values for your yarn in the integrated yarn database.

Enter the values for A to C.

Wanted yarn thickness

I have

  • the thickness of my known yarn A
    in dD,
  • my present pricking B, which is ideal for my yarn. Now I want to change the size of this pricking and
    I enter the desired pricking size under C. According to this formula, the yarn thickness I am looking for is given in dD.

*Enter either total size in cm or pin distance in mm Log in to thread database

Wanted pricking size

I have

  • the thickness of my known yarn A
    in dD,
  • my present pricking size B, which is ideal for my yarn. Now I want to use another yarn with a known yarn thickness in dD. According to this formula, the pricking size I am looking for is given in the previously agreed unit.

*Enter either total size in cm or pin distance in mm Log in to thread database


Explanations on the handling
with dD values

When making bobbin lace we are often faced with the decision which yarn to use for my lace pricking. There is an abundance of yarns on the market and it is often not easy to find the right yarn thickness and material for the pricking. Sometimes an exact make and brand name is given, but that yarn may not be available. Those who have many years of experience with lace prickings will certainly know which material to resort to as an alternative. In the following, I offer you specific help on how to find appropriate yarns and alternative yarns for your prickings and also how large the lace prickings (pin distances) should be for your yarn.


Information 1 – What is dD?

In 1988, I developed a measuring system for my doctorate in Belgium that indicates the actual diameter of round yarns. Yarns needed for bobbin lace predominantly have a round cross-section. In this system, one unit of diameter corresponds to 10 micrometres. 

  •     A yarn with dD 100 (1000 micrometres) is 1 mm thick. 
  •     A yarn with dD 30 (300 micrometres) is 0.3 mm thick.
  •     A yarn with dD 20 (200 micrometres) is 0.2 mm thick.
  •     A yarn with dD 10 (100 micrometres) is 0.1 mm thick.

The dD number therefore actually increases linearly with increasing yarn thickness. 

I always refer to average thicknesses because, for example, linen contains yarn parts of different thicknesses due to growth. Hence the designation dD (average diameter).

Information 2 – Dependence between
pin distance and thread thickness

Bobbin lace is made on lace prickings. Especially laces that are pre-drawn on a grid, such as torchon, Flanders lace, tulle.... are closely dependent on grid size and thread thickness. In order to obtain an appropriate density and transparency, the prickings are bound to certain yarn thicknesses. I present common grids for bobbin lace here, which are not classified by angles but by pin distances from horizontal edge to vertical edge.


The basis is always a square with a certain number of horizontal and vertical pin distances. The number depends on the lace types.
Torchon: 10/10 distances
Point de Paris: 6/10 distances
The pin spacing is MOST IMPORTANT, it is always indicated separately.


Example 1

Information 3 – Measuring
the distance between pins

It is difficult to measure the distances between 2 pins accurately. That’s why you do not measure between 2 pins, but for practical reasons between 11 pins instead. There are 10 pin distances between 11 pins. So you measure 10 pin distances at the left vertical edge and divide the result by 10, see above. 10 pin distances result in 65 mm. The distance between 2 pin points is 6.5 mm.


Example 2

There is a connection between the pricking sizes and the yarn thicknesses: The large pricking is 1.625 x (62.5 %) larger than the second. The yarn should then also be 1.625 x thicker than the yarn in the small pricking. The selected yarn has the number dD 22 (22 x 1.625 = 35.75). The yarn from the large pricking has the number dD 35. The dD values therefore relate to each other in the same way as the prickings. There are numerous other marking systems, but only with the dD values this linear relationship can be represented and thus we can find suitable yarns for the lace prickings relatively easily. If the grid is enlarged, the yarn must also be correspondingly thicker if we want to obtain the same density. For a 10 percent enlargement of the pricking, +10 % of the yarn thickness must be chosen. This is guaranteed with the dD values:


Information 4 - Basics for finding
yarn thicknesses and pricking sizes

To find an unknown value I need 3 known values:


  1. The pricking size (pin distance)
  2. The yarn thickness
  3. The new desired pricking size (pin distance) or the yarn thickness.

To make it even easier, you can use the following formulas for free:

1.  What yarn thickness do I need??

Pricking 1 above has a grid size of 6.5 mm (pin distance) yarn dD ±35
Pricking 2 has a grid size of 4 mm (pin distance), which yarn do I need?

65 40   
35 x   

Result: dD ±22 (the exact value is: 21.538 – round up here). 
The result would allow the range dD 21 – 23.

You can find the right yarn recommendations here:
Test yourself, enter the numbers in the dD calculator at the beginning of this information.

Example 1 – Application

65 40
35 x


So you need a yarn ± dD 22, see yarn table/sorting by dD values in the yarn database.


or example 2

65 55
35 x


So you need a yarn ± dD 28, see yarn table/sorting by dD values in the yarn database.

2. What pin distance do I need for my yarn?

You can also start from a yarn you want to work with. You know what thickness you used to make your pricking. Or look at the examples above and then enter the dD number of your yarn. To do this, look in the thread table under “manufacturers” and find your yarn there. You can then use the formula below to calculate the size of 10 distances or the pin distance from the edge.


Previous lace pricking

Total length: 7 cm

Yarn specification: Egyptian cotton no. 60/2 = dD16

Desired pricking size: 5 cm

Now I need which yarn?


Answer: dD 11.4 Yarns of dD 11 to 12 are recommended.
The yarn offers can be found in the database – 
thread table – sorted by dD.

Next, the classic bobbin laces are presented with their grids, i.e., their basic elements. Each of these lace types has its own typical grid and empirical values for the yarn recommendation per pin distance.


Each grid is accompanied by a bobbin lace sample with the corresponding thread thickness, so that the density is adequate. The grids are intended to illustrate on which grids the following laces will be made. They are not a basis for actual lace prickings because the size can be distorted by the screen.

Flanders lace, 10/10 distance (8 threads per pin [mesh]) 
Point de Paris, 6/10 distance (8 threads per pin [mesh])

Tulle always shows a grid around 60 degrees with 4 threads per pin
The following pin distances are common: Tulle 1; 8/14, Tulle 2; 10/17 Tulle 3; 7/12 Tulle 4: 5/10 

Tulle 1
Tulle 2
Tulle 3
Tulle 4

This ground always features a distance ratio of 8/10

Mechlin lace

This ground always features a distance ratio of 16/14