Merge sort
![](/Images/godic/202412/21/Merge-sort-example-300px5354.gif")
![Merge sort animation. The sorted elements are represented by dots.](/Images/godic/202412/21/Merge_sort_animation25355.gif")
![A recursive merge sort algorithm used to sort an array of 7 integer values. These are the steps a human would take to emulate merge sort (top-down).](/Images/godic/202412/21/Merge_sort_algorithm_diagram.svg5355.png")
![Merge sort type algorithms allowed large data sets to be sorted on early computers that had small random access memories by modern standards. Records were stored on magnetic tape and processed on banks of magnetic tape drives, such as these IBM 729s.](/Images/godic/202412/21/IBM_729_Tape_Drives.nasa5355.jpg")
In computer science, merge sort (also commonly spelled mergesort) is an efficient, general-purpose, comparison-based sorting algorithm. Most implementations produce a stable sort, which means that the implementation preserves the input order of equal elements in the sorted output. Mergesort is a divide and conquer algorithm that was invented by John von Neumann in 1945. A detailed description and analysis of bottom-up mergesort appeared in a report by Goldstine and Neumann as early as 1948.