Key Takeaways
- The average Social Security benefit in 2025 is $1,976/month, or $23,712/year. Over a 20-year retirement, that totals $474,240 in nominal income before any cost-of-living adjustments.
- Calculators that ignore Social Security often overstate your required portfolio by $300,000 to $600,000, causing unnecessary over-saving in low-priority accounts.
- Use a calculator that lets you enter your expected Social Security benefit as a separate income stream, then model your portfolio to cover only the remaining income gap.
- Tool: Run your retirement number with Social Security factored in →
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Most Retirement Calculators Do Not Include Social Security by Default
The majority of widely used retirement calculators treat your investment portfolio as your only income source. They ask for your current savings, your monthly contribution, an assumed rate of return, and a target retirement age. They output a single number: the portfolio balance you need to sustain withdrawals for 20 or 30 years.
Social Security does not appear in that math unless you explicitly add it.
This is not a minor omission. The Social Security Administration reports that Social Security replaces approximately 37% of pre-retirement income for the average worker. For a household earning $120,000 per year before retirement, that is roughly $44,400 in annual income the calculator silently ignores.
Some calculators, including the SSA's own Retirement Estimator and a handful of financial planning tools, do accept Social Security input. But many consumer-facing tools do not. Knowing which type you are using changes the target number entirely.
The Dollar Gap When Social Security Gets Left Out
Excluding Social Security from a retirement projection inflates the required portfolio by a specific, calculable amount.
Use the standard 4% withdrawal rule as the baseline. Under this rule, a retiree needs a portfolio 25 times their annual income gap. If you need $80,000 per year in retirement and Social Security will cover $24,000 of that, your actual income gap is $56,000. Your required portfolio is $56,000 x 25, which equals $1,400,000.
A calculator that ignores Social Security tells you to accumulate $80,000 x 25, or $2,000,000.
The difference is $600,000. That is not rounding error. That is a decade of additional saving for many households, or years of unnecessary delay in retirement.
Worked Example 1: Married Couple, Ages 62 and 60
A married couple plans to retire when the older spouse turns 67. Their combined Social Security benefit, based on their Social Security Statement from SSA.gov, is projected at $4,200/month in today's dollars, or $50,400/year.
They estimate they need $105,000/year in retirement income to maintain their lifestyle.
Without Social Security in the calculator: Required portfolio = $105,000 x 25 = $2,625,000
With Social Security included: Income gap = $105,000 - $50,400 = $54,600 Required portfolio = $54,600 x 25 = $1,365,000
The couple's actual savings target is $1,260,000 lower than the calculator without Social Security suggested. If they have been targeting $2,625,000, they may already be in a position to retire earlier than they planned, or redirect excess savings toward taxable brokerage accounts with greater flexibility.
Worked Example 2: Single Earner, Age 55, Planning for Age 65 Retirement
A single professional, age 55, earns $95,000/year and expects Social Security of $2,100/month ($25,200/year) if claimed at full retirement age of 67. She plans to retire at 65 and bridge the two years before Social Security begins with portfolio withdrawals.
Her retirement income target is $75,000/year.
Phase 1 (ages 65 to 67, no Social Security): She needs $75,000/year entirely from her portfolio for two years. That is $150,000 in withdrawals.
Phase 2 (age 67 onward, Social Security active): Income gap = $75,000 - $25,200 = $49,800/year Required portfolio at 67 = $49,800 x 25 = $1,245,000
Total portfolio needed at age 65: She needs $1,245,000 at age 67, plus $150,000 to cover ages 65 to 67, plus portfolio growth assumptions. Assuming a 6% nominal return over the two-year bridge, she needs approximately $1,257,600 at retirement, not the $1,875,000 a Social Security-blind calculator would produce.
A two-year claiming delay also increases her Social Security benefit by roughly 16%, from $25,200 to approximately $29,200/year, which reduces the Phase 2 income gap further.
How to Find Your Social Security Estimate Before You Run the Numbers
Your Social Security Statement is the only authoritative source for your projected benefit. The SSA updates it annually and makes it available through my Social Security at ssa.gov/myaccount.
Your statement shows projected monthly benefits at three claiming ages: 62, your full retirement age (66 or 67 depending on birth year), and 70. The difference between claiming at 62 versus 70 is typically 76% more monthly income at 70. For a worker projecting $1,800/month at 62, that is $3,168/month at 70.
Pull this number before you run any retirement projection. Enter the monthly benefit that matches your planned claiming age, not the earliest or latest option by default.
What to Look for in a Retirement Calculator That Handles Social Security Correctly
A calculator that accounts for Social Security correctly will do four things:
First, it accepts your monthly Social Security benefit as a separate income field, not bundled into a generic "other income" line.
Second, it applies the benefit starting at the age you specify, not at a fixed assumed age.
Third, it applies a cost-of-living adjustment (COLA) to the Social Security income stream. The SSA has applied an average COLA of approximately 2.6% per year over the past 20 years.
Fourth, it calculates your portfolio withdrawal requirement as the income gap after Social Security, not total income need.
If the calculator you are using does not do all four of these, you are calculating a savings target for a retirement that assumes Social Security does not exist.
Run Your Actual Number
The CalcMoney retirement calculator accepts your expected Social Security benefit as a dedicated income input. Enter the monthly amount from your SSA statement, the age at which you plan to claim, and your target annual retirement income. The calculator isolates your portfolio's required contribution and shows the gap your investments actually need to fill.
If you have old 401(k) accounts from previous employers sitting unclaimed, Capitalize can locate them and handle the rollover to your current plan at no cost, consolidating the assets that feed into this projection.
Your real retirement number is almost certainly lower than what a default calculator shows. Run it with the full picture.
You Might Also Like
- Retirement Income Calculator With Social Security: Timing Your Claim for Maximum Lifetime Benefits
- How to Calculate Social Security Break-Even Age Before You Claim
- Social Security Delayed Retirement Credits: The Exact Math Behind Waiting
Results are estimates for informational purposes only. Consult a licensed financial professional before making financial decisions.
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