Why the mid-1980s price level matters
The phrase ‘in the 1980s’ is too broad for a precise conversion. Prices changed throughout the decade, so use the year printed on the record.
A$100 in 1980, 1985 and 1989 starts from a different price level even though the face amount is identical.
Choose the period that matches your record
A calendar-year amount, a financial-year account and a purchase from a particular quarter do not cover the same dates.
Use the period written on the record. Two results can differ slightly when one covers a calendar year and the other a financial year.
| Period | Use when | Caution |
|---|---|---|
| Calendar year | Record belongs to a named year | Four calendar quarters |
| Financial year | Budget or account uses FY | Spans two calendar years |
| Quarter | Dated purchase | More time-specific |
What the result does—and does not—measure
CPI shows roughly what the amount would be worth today. Electronics, homes, university costs, wages and petrol may have moved by different amounts.
Use the CPI result as a starting point, then check prices for the particular item or earnings figures if that is the real question.