A cost-of-living index turns messy local prices — rent, groceries, transport, eating out — into a single comparable number, usually anchored to a reference city. Numbeo's widely used index, for example, sets New York City at 100, so a city scoring 45 is roughly 55% cheaper for a comparable lifestyle.
Indexes are directional, not precise: they reflect average baskets and move with exchange rates, so your real costs depend on your lifestyle and where exactly you live. They're best for ranking and rough comparison, not budgeting to the dollar.
Why it matters for your move
A cost-of-living index is the fastest way to compare affordability across dozens of places at once — the starting filter before you dig into the real numbers for the handful you're serious about.