Indexation is adjusting an amount according to movements in a specified index. A wage, pension, contract price or financial payment might be linked to a consumer price index so that it changes as the measured price level changes.
The adjustment depends on an established rule. It is not a requirement that all wages, government spending or insurance cover automatically rise by the latest inflation rate.
How does indexation work?
An index summarizes changes in a defined set of prices or other values. The US Bureau of Labor Statistics explains how consumer price indexes can be used in escalation agreements, meaning arrangements that adjust payments over time.
A simple formula for full price indexation is: new payment = original payment × new index ÷ original index. The two index levels must come from the same series and use the reference periods specified in the rule.
The details can change the result. Some agreements adjust only once a year, use data published months earlier, limit increases with a cap or prevent reductions with a floor. A fixed annual increase is not necessarily indexation, because it may not depend on any index.
What is the difference between index points and percentages?
Suppose a fictional price index rises from 240 to 252. That is an increase of 12 index points, but the percentage increase is 12 ÷ 240 × 100 = 5%.
If a fictional monthly payment of $2,000 is fully linked to that change, the new amount is $2,000 × 252 ÷ 240 = $2,100. It rises by $100, not by 12%.
Applying the formula to the index levels avoids confusing the index’s scale with an inflation rate. The example assumes no cap, floor, timing lag or additional adjustment.
Does indexation preserve purchasing power?
It can help an amount keep pace with the chosen measure of prices. Purchasing power means how much money can buy, while a real value is a value adjusted for a specified price measure.
However, an average basket is not identical to one household’s spending. A person whose rent or energy costs rise faster than the index may still find that a fully indexed income buys less of what they personally need. Taxes and the timing of an adjustment can also matter.
How are government bonds indexed?
Some government debt links payments to inflation. For US Treasury Inflation-Protected Securities, or TIPS, the principal adjusts with a specified consumer price index. The fixed interest rate is applied to that adjusted principal.
TreasuryDirect explains that TIPS principal can move down with deflation as well as up with inflation. At maturity, the payment is the greater of the adjusted principal and original principal. That floor does not guarantee a profit for someone who paid a higher market price or sold before maturity.
UK index-linked gilts use the Retail Prices Index, or RPI, with a lag. The UK Debt Management Office explains that their coupons and principal payments are adjusted, and cash flows can fall when the relevant index falls. Their design should not be assumed identical to TIPS.
Where else is the term used?
Wage agreements, pension arrangements, rents and insurance limits may contain indexation rules. The amount, reference measure and adjustment frequency depend on the specific arrangement.
Some tax systems also index selected thresholds or asset costs, but the rules differ across countries and can change. There is no universal entitlement to inflation-adjust a capital gain, and not everyone or every investment is subject to the same capital gains tax.
“Indexing” can mean the same adjustment process in this context. In investing, it can instead mean following a market index through an index fund. That is a separate use of the word, rather than a reason to treat indexing and indexation as always different.
Last checked and updated on November 2, 2026 by the MBN editorial team.