There is no single age at which a company stops being a startup in every context. A statistical agency may define the term by firm age, while founders and investors often use it for an organization still searching for a repeatable, scalable model. State the definition you are using before comparing companies.
The statistical meaning
A U.S. Small Business Administration Office of Advocacy study used 'startup' for firms less than one year old in its analysis of survival rates and firm age. That is a precise measurement choice for a dataset, not a rule that a one-year-old venture must be mature. Other reports may count new establishments rather than new legal companies, so definitions are not directly interchangeable.
If a headline says that a certain percentage of startups survive, inspect the cohort, geography, time period, and whether the unit is a firm or a location. The outcome for a new local shop cannot be inferred from a venture-backed technology sample without checking these differences.
The operating meaning
In everyday business discussion, startup often refers to uncertainty: a team is validating a customer problem, product, revenue model, or route to scale. The organization may be several years old while still testing these fundamentals. Conversely, a recently founded firm can operate a familiar, stable service model and may not be called a startup in the venture-capital sense.
Funding stage is another shorthand, but it is imperfect. Receiving a seed round does not prove product-market fit, and being profitable does not automatically end experimentation. The question is what kind of risk the company is resolving and whether the core model is repeatable.
Signals of a transition
A company may feel less like a startup when demand is predictable, the product and delivery process are stable, teams have defined responsibilities, and growth no longer depends on reinventing the model each quarter. These are indicators rather than a certification. A mature company can launch a new product with startup-like uncertainty inside it.
For a customer, employee, or supplier, the practical issue may be reliability and financial capacity rather than the label. Ask for relevant evidence: service history, support, contracts, governance, and ability to deliver. For an investor, examine current financial and operating data instead of treating age as a proxy for opportunity.
A useful way to answer
Say 'startup' according to the purpose of the discussion: a firm under one year old in a particular statistical report, or a venture still testing a scalable business model in strategy talk. When a document sets an eligibility cutoff for a grant, accelerator, or program, its own definition controls. Do not impose an informal five- or ten-year rule where none exists.