# Square Millimeters and Square Inches Converter

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## Converting square inches and square millimeters

In the conversion tables below, figures are rounded to a maximum of 5 decimal places (7 with smaller numbers) to give approximations.

Square Inches | Square Millimeters |
---|---|

1 square inch | 645.16 square millimeters |

2 square inches | 1290.32 square millimeters |

3 square inches | 1935.48 square millimeters |

4 square inches | 2580.64 square millimeters |

5 square inches | 3225.8 square millimeters |

6 square inches | 3870.96 square millimeters |

7 square inches | 4516.12 square millimeters |

8 square inches | 5161.28 square millimeters |

9 square inches | 5806.44 square millimeters |

10 square inches | 6451.6 square millimeters |

11 square inches | 7096.76 square millimeters |

12 square inches | 7741.92 square millimeters |

13 square inches | 8387.08 square millimeters |

14 square inches | 9032.24 square millimeters |

15 square inches | 9677.4 square millimeters |

16 square inches | 10322.56 square millimeters |

17 square inches | 10967.72 square millimeters |

18 square inches | 11612.88 square millimeters |

19 square inches | 12258.04 square millimeters |

20 square inches | 12903.2 square millimeters |

Square Millimeters | Square Inches |
---|---|

1 square millimeter | 0.00155 square inches |

2 square millimeters | 0.0031 square inches |

3 square millimeters | 0.00465 square inches |

4 square millimeters | 0.0062 square inches |

5 square millimeters | 0.00775 square inches |

6 square millimeters | 0.0093 square inches |

7 square millimeters | 0.01085 square inches |

8 square millimeters | 0.0124 square inches |

9 square millimeters | 0.01395 square inches |

10 square millimeters | 0.0155 square inches |

11 square millimeters | 0.01705 square inches |

12 square millimeters | 0.0186 square inches |

13 square millimeters | 0.02015 square inches |

14 square millimeters | 0.0217 square inches |

15 square millimeters | 0.02325 square inches |

16 square millimeters | 0.0248 square inches |

17 square millimeters | 0.02635 square inches |

18 square millimeters | 0.0279 square inches |

19 square millimeters | 0.02945 square inches |

20 square millimeters | 0.031 square inches |

### How many square millimeters are there in 1 square inch?

There are 645.16 square millimeters in 1 square inch. To convert from square inches to square millimeters, multiply your figure by 645.16 (or divide by 0.0015500031000062) .

### How many square inches are there in 1 square millimeter?

There are 0.0015500031000062 square inches in 1 square millimeter. To convert from square millimeters to square inches, multiply your figure by 0.0015500031000062 (or divide by 645.16) .

### What is a square inch?

A **square inch** is a common unit of measurement within the United States and the United Kingdom. It can be used throughout numerous industries such as construction, graphic design, textiles and painting. Some common abbreviations include sq. in., sq. inches and in/-2. One square inch can approximate the size of many postage stamps. A single square inch is equal to 6.45 square centimeters.

### What is a square millimeter?

The **square millimeter** (or 'millimetre' with British spelling) is a unit defined as a square with each side measuring one millimeter in length. This is abbreviated simply as mm^{2}. This is quite a small area, for an average-sized playing card measures 5,600 square millimeters (56 square centimeters). Square millimeters can be used when designing smartphone screens or determining the total area occupied by an electrical component on a circuit board. Another application can be mapping the scalp before a hair transplantation process takes place.

### Other individual area converters

Square Inches and Acres, Square Inches and Square Centimeters, Square Inches and Square Feet, Square Meters and Square Inches, Square Millimeters and Cents, Square Millimeters and Square Centimeters, Square Millimeters and Square Feet, Square Millimeters and Square Inches, Square Millimeters and Square Meters,