One metre is 39.3700787402 inches. That number has a historical importance out of proportion to its everyday use: for nearly a century, 39.37 inches per metre was the legal definition of the metre in the United States, and the tiny gap between that and the modern value created a second kind of foot that survived until 2022.
About the units
The metre has been defined by the speed of light since 1983, but the United States adopted it as a legal reference much earlier. The Mendenhall Order of 1893 defined American length units in terms of the metre rather than the other way round, and it used the relationship 1 m = 39.37 inches exactly. The inch itself, in that arrangement, was therefore 100/3937 metres. When the international agreement of 1959 redefined the inch as exactly 25.4 mm, the two definitions no longer matched: 39.37 in gives an inch of 25.4000508 mm, slightly longer than the new international inch.
The exact factor
Under the modern definition, 1 m = 1000 ÷ 25.4 = 39.37007874015748... inches, repeating. Under the old American definition it was exactly 39.37. The difference is two parts per million — about 0.08 mm across a metre, or roughly 3 cm across fifteen kilometres. That sounds negligible, and it is for nearly everything, but it is not negligible for land surveying across a state, which is why the US survey foot continued to exist alongside the international foot until it was formally retired at the end of 2022.
Where you meet this conversion
Direct metre-to-inch conversion turns up wherever a metric specification meets an imperial tool: sheet goods, pipe lengths, fabric bolts, and rope or cable sold by the metre but fitted with imperial hardware. It is also the conversion behind screen and print dimensions when a metric page size has to be expressed in inches — A4 is 210 × 297 mm, which is 8.27 × 11.69 inches, and the untidiness of those numbers is exactly why American Letter paper is a different shape.