One eighth of an inch is equal to approximately 3.175 millimetres. The following link will lead you to a website which will help you to convert inches to millimetres in future: mdmetric.com/tech/cvtcht.htm One full international inch equals exactly 25.4 millimetres.

An inch is defined as a unit of length that is used in a great number of different systems including the Imperial system and the United States customary units.

There are 36 inches in a yard and 12 inches in a foot.

The inch is the most commonly used unit of measurement in the United States and is still widely used in the United Kingdom and Canada, despite the introduction of the metric system to the latter two countries. The inch can also sometimes used in Australia and other Oceania countries.

The millimetre is defined as a unit of measurement for length that is used in the metric system. One millimetre is equal to one thousandth of a metre. It is also equal to 1,000 micrometres and 1,000,000 nanometres, a unit of measurement most commonly used in scientific fields.

This unit of measurement is not greatly used unless there is a need for very small or minute measurements such as in designing.

Hardly anyone can just convert units into others in their head, unless they know the exact conversion rate and are very good at doings big sums mentally. But nowadays, most cell phones now have conversion applications that are built into them when you first buy them, without having to download anything. If you are near a computer or your phone doesn't have a conversion application then you can just use one of the dozens of websites that are out there. These are really useful because they will give you the exact amount to the correct number of decimal places without rounding up.

An inch is defined as a unit of length that is used in a great number of different systems including the Imperial system and the United States customary units.

There are 36 inches in a yard and 12 inches in a foot.

The inch is the most commonly used unit of measurement in the United States and is still widely used in the United Kingdom and Canada, despite the introduction of the metric system to the latter two countries. The inch can also sometimes used in Australia and other Oceania countries.

The millimetre is defined as a unit of measurement for length that is used in the metric system. One millimetre is equal to one thousandth of a metre. It is also equal to 1,000 micrometres and 1,000,000 nanometres, a unit of measurement most commonly used in scientific fields.

This unit of measurement is not greatly used unless there is a need for very small or minute measurements such as in designing.

Hardly anyone can just convert units into others in their head, unless they know the exact conversion rate and are very good at doings big sums mentally. But nowadays, most cell phones now have conversion applications that are built into them when you first buy them, without having to download anything. If you are near a computer or your phone doesn't have a conversion application then you can just use one of the dozens of websites that are out there. These are really useful because they will give you the exact amount to the correct number of decimal places without rounding up.