There is no magic number, and anyone who gives you one, four letters, two syllables, under seven characters, is selling a rule that its own famous examples break. The useful target is not short. It is short-feeling: a name that is fast to say, easy to hold in memory, and clean to type, regardless of its exact letter count.
Length matters, but it matters through those three effects, not on its own. A name can be long and feel short, or short and feel like a chore. Once you optimize for the feeling instead of the character count, most of the received wisdom falls apart.
Why two to three syllables dominates
If you list the brand names that stick, most land at two or three syllables, and there is a mechanical reason. That range fits comfortably in working memory as a single chunk, says in one relaxed breath, and carries enough distinct sound to be ownable. It is the band where memorability and distinctiveness overlap.
Push below it and you tend to lose distinctiveness. A one-syllable name like Vox or Ohm is easy to say but collides with a hundred other things, real words, initials, existing brands, so you spend your life adding qualifiers to be understood. Push above it and users edit the name for you: a four- or five-syllable name gets abbreviated to a nickname you did not choose, which means you built brand equity in syllables people throw away. Two to three is the range where the name you launch is the name people actually use.
The radio test and the text-a-friend test
Two quick tests predict length problems better than any character count. The radio test: say the name aloud in a normal sentence, 'I found it on Renlo,' and see if a listener could act on it without you spelling anything. If the name needs a spelling appended every time, it is functionally longer than it looks, because each mention now costs an extra clause.
The text-a-friend test: say the name once and ask someone to type it. This is where respellings die. Fyx, Kwik, and Zeel are short on screen but expensive in life, because every person who hears them types the obvious spelling first, lands nowhere, and gives up. A slightly longer name that types itself correctly on the first try beats a four-letter name that never does.
When a longer name wins anyway
Length is a liability you can buy back with rhythm and meaning. A longer name earns its keep when it has cadence, a compound like Fernpost or Basecamp that reads as one confident unit rather than two words stapled together, or when the extra length carries real meaning a short coinage cannot. Meridian Freight is not short, but it says something and it sounds like a company you would trust with a container, which for a B2B logistics buyer is worth more than brevity.
Longer also wins when the name is destined to be shortened well. If a five-syllable name collapses into a strong two-syllable nickname you actually control and can own, the full form can carry gravitas while the short form does the daily work. The failure mode is a long name whose abbreviation is generic or ugly; then you get the length cost without the short-form payoff.
How length collides with domain availability
Here is the practical squeeze. The shorter the name, the more likely its .com is long gone or priced like a used car. Effectively every four- and five-letter .com is registered, and the good ones trade for four and five figures. So the hunt for a genuinely short name pushes you toward respellings and dropped vowels, the Lyfts and Fiverrs, each of which levies a permanent spelling tax on every customer for the life of the brand.
This is exactly why short-feeling beats short. A six-to-eight-letter coined name at two syllables, think Veloro or Otterly, reads as fast and light as a four-letter name, types correctly on first hearing, and is far more likely to have an available, correctly spelled domain. You get the perception of shortness without paying the squatter's premium or the respelling tax. When people insist on a tiny name, they are usually optimizing the character count and ignoring the two costs that actually hurt.
The cargo cult of four letters
The 'four letters or die' advice is survivorship bias wearing a suit. The famous four- and five-letter names are memorable because of the billions in marketing and years of ubiquity behind them, not because of their length, and for every one you can name there are thousands of dead four-letter startups you cannot, precisely because a tiny name did nothing to save a business with nothing behind it. Meanwhile a large share of dominant brands run seven, eight, nine letters and no one notices, because those names feel short where it counts: in the mouth and in the memory.
So stop counting letters. Ask whether the name says in one breath, types itself from hearing, and holds in memory as a single chunk. A brand name generator that reports syllable count, spelling risk, and real domain availability alongside each candidate will tell you far more about whether a name is the right length than any letter-count rule ever could.