Annualized Rate
When the US Bureau of Economic Analysis reports quarterly GDP, it publishes the number as a "seasonally adjusted annual rate" (SAAR). This means: take the growth recorded in those three months, and mathematically project it across four quarters. Suppose the economy grew 1% in a single quarter; annualizing that produces roughly 4% — not because the full year actually delivered 4%, but because the quarterly pace, if sustained, would. The conversion uses compounding: (1 + quarterly rate)⁴ − 1.
The US convention is not universal. Many other countries simply report the actual quarter-on-quarter percentage change, or the year-on-year change versus the same quarter last year. This creates a genuine comparison trap: a US "3% GDP growth" headline and a European "0.7% GDP growth" headline might describe nearly identical underlying economies in that quarter, just expressed differently. Always check which convention a report uses before comparing across borders.
Annualized rates also appear in inflation, industrial production, and trade data — anywhere a short-period reading is stretched to an annual pace for easier interpretation. The approach amplifies both good and bad news: a single weak quarter can print as an alarming negative annual rate even if the surrounding quarters are healthy. Real GDP reports on the indicators page note the convention used so readers can interpret the number correctly.