COLA Ledger

An independent reference — not affiliated with the Social Security Administration. Every figure traced to the government publication that produced it.

The 1998 Social Security COLA — 2.1%

Cost-of-living adjustment, 1998

2.1%

This adjustment was determined in 1997, took effect with benefits payable for December 1997, and first reached checks in January 1998.

Determined in
1997December-effective
First in a check
January 1998
Comparison quarter
Q3 1997CPI-W 157.9
Base quarter
Q3 1996CPI-W 154.6

SSA’s own table lists this adjustment under 1997, the year it was determined. The public name it by the year it reaches a check, which is one later. This site uses the name people search for. Why the two labels disagree.

The CPI-W values behind the 2.1%

Every adjustment is an average of three monthly index readings against an average of three others. These are the six values, as the Bureau of Labor Statistics published them for series CWUR0000SA0 — all items, U.S. city average, not seasonally adjusted.

CPI-W monthly index values and quarterly averages behind the 1998 adjustment
QuarterMonthCPI-W index
Base — Q3 1996July 1996154.300
August 1996154.500
September 1996155.100
Base quarter average154.6
Comparison — Q3 1997July 1997157.500
August 1997157.800
September 1997158.300
Comparison quarter average157.9

The quarterly averages are rounded to the nearest tenth — the precision the determination-1997 notice specifies — and the percentage increase between them is then rounded to the nearest tenth of a percentage point. That gives 2.1%.

Reproduced from the raw index

Recomputing this adjustment from the committed CPI-W series returns 2.1%, matching SSA’s published figure. That check runs on all 51 determinations as a blocking build gate, so no page here can ship a figure the arithmetic does not support.

What 2.1% did to a benefit

Monthly benefit amounts are floored to the whole dollar after the adjustment is applied, which is why these figures are not simply the percentage multiplied out.

Effect of the 1998 adjustment on two benchmark monthly benefits
Monthly benefit beforeAfter the adjustmentMonthly increaseOver a year
$1,000$1,021+$21+$252
$2,000$2,042+$42+$504

The 1998 figures this adjustment set

Most Social Security parameters move with the adjustment or with the national average wage index. These are the committed values for 1998, each traced to the government table it came from.

Committed Social Security and Medicare parameters for 1998
Parameter1998
Maximum earnings subject to Social Security tax$68,400
SSI federal payment rate — individual$494
SSI federal payment rate — couple$741
Earnings needed for one Social Security credit$700
Retirement earnings test — under full retirement age$9,120
Retirement earnings test — year of full retirement age$14,500
Substantial gainful activity — non-blind$500
Substantial gainful activity — blind$1,050
Trial work period — a service month$200
First PIA bend point (eligibility at 62 this year)$477
Second PIA bend point (eligibility at 62 this year)$2,875

Where to go next

Sources and freshness

Figures effective December 1997. Page figures last verified against the sources above on 10 August 2026. BLS data retrieved 10 August 2026. BLS.gov cannot vouch for data or analyses derived from these data after retrieval. Corrections: the correction log · support@inventum.com.au