File conversion tools

File conversion tools transform a file from one format into another so that it can be opened, edited or played by a different program. Because each format stores data in its own structure — whether a document, spreadsheet, image, audio clip or video — a converter must read the original encoding and rewrite the content according to the rules of the target format. Conversion is needed when software cannot open a file, when a smaller or more portable format is wanted, or when content must move between operating systems and devices.

The simplest converters handle a single family of data. Image converters move between formats such as BMP, PNG, JPEG and TIFF; document converters translate between word-processor formats and PDF; and audio or video converters re-encode media using different codecs. Many tools support batch processing, converting many files at once with consistent settings, which is useful for large collections of photographs or scanned documents.

An important distinction is between lossless and lossy conversion. Lossless conversion preserves all of the original information, so the data can be recovered exactly. Lossy conversion — common with JPEG images and compressed audio and video — discards some detail to reduce file size, and repeatedly re-saving such files can degrade quality. Some conversions are also only approximate because the target format cannot represent every feature of the source, such as complex layout or embedded objects. Choosing the right format and settings therefore involves balancing compatibility, file size and fidelity.

Frequently asked questions

What is the difference between lossless and lossy conversion?

Lossless conversion keeps all the original data intact, while lossy conversion discards some detail to shrink the file, which can reduce quality.

What is a codec?

A codec is a method for encoding and decoding audio or video data. Converting media between formats often means re-encoding it with a different codec.

Why does some content change after conversion?

If the target format cannot represent every feature of the source, such as complex formatting, the converter must approximate or drop those elements.