.com vs .io vs .ai: Which Should a Startup Actually Use?
The extension debate is usually argued on vibes. Here it is argued on cost: over five years the same domain runs about $55 in .com, $235 in .io and $414 in .ai, and that is before anyone mentions credibility.
September 21, 20266 min readTLDs · Startups · Pricing
The short answer. Take the .com if you can get it, because everyone will type it regardless of what you print. If you cannot, .io and .ai are both viable and both carry real costs: over five years the same name runs roughly $55 in .com, $235 in .io and $414 in .ai, and that is at the cheapest registrar rather than the typical one.
The cost nobody compares
Most extension arguments never mention money, which is odd, because the difference is not marginal.
These are five-year totals, one registration plus four renewals, from live registrar pricing pulled on 21 September 2026. The range is cheapest to most expensive across four registrars for the same domain.
| Extension | Cheapest over 5 years | Most expensive | Difference |
|---|---|---|---|
| .com | $54.40 | $89.95 | $35.55 |
| .io | $235.32 | $331.95 | $96.63 |
| .ai | $413.50 | $1,129.90 | $716.40 |
Two things follow.
.ai is in a different category of expense. A single .ai can cost you $414 or $1,130 over five years depending on nothing but which registrar you picked. If you run ten of them, the wrong choice costs over $7,000.
The registrar matters more than people think, and more at higher price points. On .com the spread is a rounding error. On .ai it exceeds the cost of the domain twice over. Full breakdown in The Cheapest Domain Registrar in 2026.
One caveat: GoDaddy's figures in that comparison come from its API's indicative pricing, which runs below its advertised retail rates, so the upper end of these ranges is conservative.
.com
The case for it is that it is the default. Not preferred, default. People hear your name and type .com without thinking. Printed materials, spoken referrals and half of all typed traffic assume it.
It is also the cheapest of the three by a wide margin, and the most stable. Verisign raises wholesale pricing roughly 7% in four years out of six, which is predictable and small in absolute terms.
The case against is that the name you want is almost certainly taken, and the aftermarket price for a decent .com starts in the low thousands.
Prices rise on 1 November 2026, from $10.26 to $10.97 wholesale, which is worth knowing if you are about to register several. See the price increase explainer.
.io
The case for it is availability and cultural fit. Short names are still obtainable, and among developers .io carries no penalty at all. Many well-known technical products run on it.
The case against is cost, roughly four times .com over five years, and the Chagos sovereignty question that produced two years of alarming headlines.
On that question: .io is operating normally, IO remains an assigned ISO 3166-1 code, ICANN has issued no retirement notice, and the treaty has stalled. Even the worst realistic outcome runs five to ten years with a transition. We went through it properly in Is .io Safe.
Watch the renewal cliff. Several registrars sell .io cheaply in year one and renew at double. The gap between registration and renewal is larger on .io than on almost any other common extension.
.ai
The case for it is that it signals category membership instantly, and for an AI product that is worth something real in a crowded market.
The case against is cost and durability. It is by far the most expensive of the three, and it is a country-code extension for Anguilla, which means it carries the same structural characteristic as .io: it exists because a small territory has a two-letter code.
The sharper risk is positional rather than technical. If your company is still operating in 2035 and the current AI wave has moved on, a .ai reads as a period marker. Some companies want that association permanently. Many do not realise they are choosing it permanently.
Registrar choice matters enormously here. The $716 five-year spread is the largest of any common extension, and it is pure waste.
How to decide
Can you get the .com of a name you like? Take it. Nothing else in this article outweighs that.
Is the .com taken by a competitor in your category? Pick a different name rather than a different extension. That is a naming problem, not an extension problem.
Is the .com taken by someone unrelated and dormant? .io or .ai is fine. Consider whether the .com is buyable later, and budget for it if the business works.
Are your customers developers? .io costs you nothing in credibility.
Are your customers non-technical? .com matters more. People will mistype, and support will spend time on it.
Is the product specifically an AI product, and will it still be one in ten years? .ai is defensible. If the answer to the second half is unclear, it is a bet.
What actually matters more
Having watched a lot of naming arguments, the extension is rarely the thing that decides anything. These matter more:
Can it be said aloud without spelling? A permanent tax, paid on every phone call.
Is it free of trademark conflict? A real risk, unlike the extension question, and much more expensive to get wrong.
Will you still like it in five years? The commonest regret is not the extension, it is the name.
Our techniques for generating candidates are in How to Come Up With a Domain Name, and you can check every extension for a name at once with our checker.
Common questions
Is .io bad for SEO?
No. Search engines treat .io as a generic extension rather than a country-specific one, and there is no ranking penalty for using it.
Is .ai worth the money?
If the AI association is genuinely central to your product and likely to remain so, it buys immediate category recognition. If it is a trend you are attaching to, you are paying roughly eight times .com for a signal that may date.
Should I buy the .com as well as the .io?
If the .com is available and affordable, yes, and redirect it. It costs little and captures traffic from everyone who assumes .com.
Which is cheapest over time?
.com, substantially. Around $55 over five years at the cheapest registrar, against roughly $235 for .io and $414 for .ai.
Does .io still have a future?
Nothing operational has changed. The code remains assigned, the registry runs normally, and any retirement process would take years with notice. The signal to watch is whether IO leaves ISO 3166-1.
Can I switch extensions later?
Technically yes, practically it is expensive. You keep the old domain redirecting indefinitely, update every external reference you can reach, and accept losing some you cannot. Choosing once is much cheaper.
Put the research to work.
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