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Social Security Delay Income Forecast Estimator

The Social Security Delay Income Forecast Estimator projects a Social Security retirement benefit forward from the age you plan to claim it. Starting with the monthly benefit you enter, it applies an annual benefit-growth assumption and a simplified tax adjustment to estimate cumulative gross and after-tax income over a selected number of years.

You can use the growth input as a scenario for future cost-of-living adjustments, but it is not a prediction of any actual COLA. The calculator also does not compute your Social Security entitlement; use an SSA benefit estimate for the starting monthly amount.

Inputs

$
age
years
%
%
%
Result
—
Projected cumulative after-tax benefits
Cumulative gross benefits—
Final-year after-tax benefit—
First-year after-tax benefit—
Forecast ending age—

1. Enter the starting monthly benefit
Use the benefit estimate associated with your intended claim age.

2. Set the claim age
This is used to show the age reached at the end of the forecast.

3. Choose the forecast length
Enter how many years of benefit payments you want to project.

4. Set annual benefit growth
Use 0% for a flat nominal benefit or another rate for a scenario with annual increases.

5. Enter tax assumptions
The calculator applies your tax rate only to the taxable share you specify.

6. Review cumulative income
Compare gross and after-tax totals along with the final-year benefit level.

The forecast compounds the entered benefit each year:

Gross benefit in year t = Monthly benefit × 12 × (1 + g)^(t−1) Net benefit in year t = Gross benefit × [1 − (Taxable share × Tax rate)] Cumulative net = Sum of annual net benefits

g is the annual benefit-growth assumption. The model uses the same tax assumptions in every year.

What the result means

The main result is the sum of modeled after-tax Social Security benefits across the forecast period. It is a scenario based on your starting benefit and growth assumption.

Actual Social Security COLAs, taxation, Medicare-related deductions, and benefit rules may differ from the assumptions entered here.

Given: $3,000 monthly benefit at age 70, 20 forecast years, 2.5% annual benefit growth, 50% taxable share, and a 22% tax rate.

Calculation: first-year gross benefit = $36,000. Net factor = 0.89, so first-year net = $32,040. Year 2 gross = $36,900 and year 2 net = $32,841. The process compounds the gross benefit by 2.5% each year.

Result: the calculator sums all 20 annual net benefits and reports the final-year benefit and ending age.

Is the annual growth input the official COLA?

No. It is a user-entered scenario. Actual Social Security cost-of-living adjustments vary by year and are determined under federal rules.

Why forecast from the claim-age benefit instead of full retirement age?

The entered monthly amount should already correspond to the age at which you plan to start benefits. That keeps the forecast separate from the claiming-age calculation itself.

Does this include taxes on my other retirement income?

No. The tax adjustment is applied only to the entered Social Security benefit using the taxable share and rate you specify.

Can the annual growth rate be zero?

Yes. A 0% growth rate produces a flat nominal benefit forecast, which can be useful as a simple baseline.

What does the ending age represent?

It is the claim age plus the forecast length. It is a timeline marker, not a longevity estimate or recommendation.