The arithmetic behind the percentages
Two rules produce every number in the table below. Claiming before full retirement age reduces the benefit by 5/9 of 1% per month for the first 36 months and 5/12 of 1% per month beyond that. Claiming after full retirement age adds 2/3 of 1% per month, which is 8% per year, and stops at 70.
For someone born in 1960 or later, full retirement age is 67. Claiming at 62 means 60 months early: 36 months at 5/9 of 1% (20%) plus 24 months at 5/12 of 1% (10%), for a 30% reduction.
| Claim age | Months from FRA | Adjustment | Percent of PIA |
|---|---|---|---|
| 62 | −60 | −30% | 70% |
| 63 | −48 | −25% | 75% |
| 64 | −36 | −20% | 80% |
| 65 | −24 | −13.3% | 86.7% |
| 66 | −12 | −6.7% | 93.3% |
| 67 | 0 | 0 | 100% |
| 68 | +12 | +8% | 108% |
| 69 | +24 | +16% | 116% |
| 70 | +36 | +24% | 124% |
What the fractions mean in dollars
The 2027 maximum benefit at full retirement age is $4,188 a month; the average retired-worker benefit is $2,170. Those are reference points for the population, not a target for any individual, and neither is adjusted by the table above — your own PIA is what gets multiplied.
Two structural facts follow from the formula:
- The early reduction is permanent. A 30% cut is applied once and never restored. The 3.6% cost-of-living adjustment for 2027 is applied to the reduced amount, so the annual increase is also 30% smaller in dollars.
- The late credit compounds the other way. At 70 a benefit is 124% of PIA, which is about 1.77 times the age-62 amount for the same worker.
The constraints that override preference
The formula does not operate in isolation. Three rules decide whether a chosen age is actually available:
The earnings test. Claiming before full retirement age while still working means benefits are withheld above $25,560 in 2027, at $1 for every $2. In the year full retirement age is reached the limit rises to $67,920 and the rate softens to $1 for every $3.
Full retirement age is 67. For anyone born in 1960 or later there is no 66-and-10-months option and no partial window. The 30% figure at 62 is the correct one for that cohort.
There is nothing to gain after 70. Delayed credits stop, so a claim at 70 captures the full 24% premium and no further waiting helps.
Health and cash needs usually decide the question before the math does. The formula only makes the price of that decision explicit.