Conversion calculator for yarn numbering systems that was distributed by The Textiles Council, Royal Exchange, Manchester. It was made between 1967 and 1971 and used to convert between various systems of measuring yarn quality.

This is a yarn conversion calculator that was distributed by the Textiles Council, who were based the Royal Exchange in Manchester. It has a movable scale that can be used to convert between the many different yarn measuring systems which had arisen from the explosive growth of the global textiles industry during the Industrial Revolution. Many buyers and manufacturers used different units of measurement to determine the quality of the yarn, but competing systems of measuring caused issues for comparison.

The Textiles Council attempted to encourage everyone to adopt a single unit for measuring yarn quality: the ‘Tex’. The Textiles Council produced these conversion calculators, placing the ‘Tex’ measurement prominently at the top, to promote the use of this measurement, which could be used across all types of yarn, including the increasingly common man-made fibres. The Textile Council sold the calculator for between 10s and 15s, roughly equivalent to £10-£15 today. Today there are still multiple units for measuring and valuing yarn, althoughthe 'Tex' is among them.

The Textiles Council existed between 1967 and 1971. It grew out of the previous Cotton Board, which began in 1948. It oversaw the organisation, research, and marketing of the UK textiles industry in a period of decline, caused by competition from outside the UK which drove down prices of cotton and other textiles.