@unique_ly I wrote a tutorial on calculating string length, that you can check out, if you want.
In this pattern the white string reaches its original position again after 24 rows. During these 24 rows, it makes knots of its own colour in 15 rows. That's 62,5% of the rows. According to my formula you then need 45cm + 62,5cm = 107,5cm per white string.
The colourful strings are used less: 11 knots in 32 rows which is 34,375%. You would need 79,375cm for each of the coloured strings.
The formula is for a 14cm long bracelet with ties on both ends.
Kallmekat_
