The amount of yarn needed for a latch hooking project depends on the lenght of the yarn used for each knot and the number of knots in a project.
Standard latch knots are made with 7,5 cm (3 inch) long lenghts of yarn for each knot.
Knotting on 13 count interlock canvas you will need approx:
For a rug of 75 x 100 cm you will need approx 900 meters of yarn. With Gordita wool you will need 11 balls.
For a rug of 100 x 150 cm you will need approx 1800 meters of yarn. With Gordita wool you will need 22 balls.
For a rug of 200 x 150 cm you will need approx 3600 meters of yarn. With Gordita wool you will need 44 balls.
Knotting on 19,7 count interlock canvas you will need:
For a rug of 75 x 100 cm you will need approx 1332 meters of yarn. With Relove wool you will need 7 skeins
For a rug of 100 x 150 cm you will need approx 2664 meters of yarn. With Relove wool you will need 14 skeins.
For a rug of 200 x 150 cm you will need approx 5328 meters of yarn. With Relove wool you will need 28 skeins.
Fringes and longer lenghts require more yarn.