Social Security pays a monthly benefit calculated from a worker's earnings record, and the age at which it is claimed adjusts that amount permanently in both directions.
The earnings record sets the base amount
The benefit begins with a figure derived from a worker's highest-earning years, indexed to reflect wage growth over the working life.
That calculation produces the amount payable at full retirement age, which is defined in law and depends on the year the worker was born.
Everything else is an adjustment to that base. Claiming earlier or later does not change the earnings record; it changes the multiplier applied to it.
Claiming early reduces the monthly amount
Benefits can be claimed before full retirement age, and doing so reduces the monthly payment by an amount that grows with how early the claim is made.
The reduction is not temporary. The lower amount continues for life, subject only to the cost-of-living adjustments applied to all benefits.
The tradeoff is straightforward in structure: more payments of a smaller amount, beginning sooner, against fewer payments of a larger one.
Delaying past full retirement age increases it
Waiting beyond full retirement age earns delayed retirement credits that raise the monthly amount, up to an age at which the credits stop accruing.
Those increases are also permanent, and they compound with cost-of-living adjustments applied to the larger base.
Delaying requires income from elsewhere during the waiting period, which is why the decision interacts with savings, employment and health rather than standing alone.
Working while claiming has its own rule
A worker who claims before full retirement age and continues earning above an annual threshold has benefits withheld under an earnings test.
Withheld amounts are not simply lost. The benefit is recalculated at full retirement age to account for months in which payments were withheld.
The earnings test stops applying once full retirement age is reached, after which work has no effect on the benefit amount.
Spousal and survivor rules add another layer
Benefits can be payable to a spouse, a former spouse or a survivor based on a worker's record, and those amounts follow their own claiming rules.
A survivor benefit in particular depends on what the deceased worker had claimed, which links one household member's timing decision to the other's outcome.
The thresholds, ages and formulas are set by statute and are periodically adjusted, so the amounts in any individual case come from the agency's own record and calculation.