Your name in Japanese
Names from other languages are written in katakana, by how they sound. Type your name to see how the Japanese names dictionary writes it, or spell it as it sounds.
Type it as it sounds
Spell your name the way it sounds, in Japanese syllables (romaji), and it turns into katakana as you type: sumisu becomes スミス and ema becomes エマ. A double letter adds a small ッ (emma becomes エッマ), and a hyphen makes a long vowel (sa-ra becomes サーラ).
Learn to read it yourself: every character is on the katakana chart, with its sound and stroke order.
How this works
The spellings come from JMnedict, the Japanese names dictionary kept by the Electronic Dictionary Research and Development Group: 67,084 names written in katakana, each with its type (a girl's or boy's name, a family name, a place, or unclassified). A name often has several spellings, because it is said differently in different languages (Michael is マイケル in English and ミハエル in German), and the dictionary doesn't say which is most common. Pick the one that sounds like you.
A name the dictionary doesn't have can still be written: spell it as it sounds and the converter gives its katakana. Foreign full names are usually written with a middle dot (・) between the parts.
Names: JMnedict (EDRDG, CC BY-SA 4.0); see attributions. Romaji and the converter: wanakana.