Reading economic numbers: percent, basis points, real versus nominal

Numbers in business. 7-minute read. Updated 2026-10-10.

Economic headlines compress a lot of maths into a few words. Misreading one term can flip the meaning of a story. Here are the ones that trip people up most.

Percent versus percentage points

If an interest rate rises from 4% to 5%, it has risen by one percentage point, which is a 25% increase in the rate. Both statements are true; they answer different questions. Good reporting says which one it means.

Basis points

A basis point is one hundredth of a percentage point, or 0.01%. A central bank that raises rates by 25 basis points has added a quarter of a percentage point. Bond traders use basis points because small moves matter on large sums.

Nominal versus real

Nominal figures are in today's money. Real figures are adjusted for inflation. If wages rose 4% while prices rose 3%, real wages rose roughly 1%. When comparing values across years, always ask which one you are looking at.

Annualised rates

Quarterly growth figures are often reported at an annualised rate, meaning what the year would look like if the quarter's pace continued. A 0.5% quarterly rise annualises to roughly 2%. Some countries report quarter-on-quarter figures without annualising, which makes international comparisons tricky.

The rule of 72

Divide 72 by an annual growth rate to estimate how many years it takes to double. At 6% a year, money doubles in about 12 years; at 9%, about 8. The rule works because 72 has many divisors and approximates 100 × ln 2 with a small correction.

Big numbers

A million seconds is about 11.6 days; a billion seconds is about 31.7 years. When a story jumps from millions to billions, it is jumping a thousandfold. Converting to per-person figures (divide by population) often makes large totals easier to judge.

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