Retirement Savings Shortfall Gap Calculator
Example: Current retirement savings: 80000 $ · Current monthly contribution: 500 $ · Expected annual return: 7 % · Years to retirement: 25 · Desired monthly retirement income: 5000 $ · Expected monthly Social Security benefit: 1800 $
| Additional monthly savings needed to close gap | $120 |
| Projected portfolio shortfall at retirement | $96,931 |
| Portfolio needed (25x annual gap above SS) | $960,000 |
| Projected portfolio on current path | $863,069 |
Worked example
With $80,000 saved, $500/month contributions, 7% return, and 25 years: the projected portfolio is $758,000. Desired income is $5,000/month; SS covers $1,800, leaving a $3,200 portfolio gap. At 25×, the needed portfolio is $960,000. The shortfall is $202,000 — requiring approximately $118 more per month to close.
Frequently asked questions
Why does this tool use 25 times the income gap?
The 25× multiplier is derived from the 4% safe withdrawal rate — the rate that has historically sustained a 30-year retirement in US portfolios. Dividing 100 by 4 gives 25. This is a planning heuristic; your actual number may be higher if you retire early (need 35+ years of income) or lower if you have substantial guaranteed income.
How accurate is this shortfall estimate?
It is a straight-line projection that does not model sequence of returns, market volatility, or tax drag. For precise planning, run multiple scenarios or consult a fee-only financial planner. This tool is best used to identify order-of-magnitude gaps and motivate action.
What if the additional monthly amount seems unaffordable?
The gap can be closed from multiple directions: saving more, delaying retirement by a few years (which dramatically reduces years needed to fund and adds compounding time), delaying Social Security to increase the SS benefit, or accepting slightly lower retirement spending. The tool isolates the savings lever; other levers also exist.
Should I include a spouse's savings?
This calculator works best for a single portfolio or a combined household view. Enter your combined savings, combined monthly contributions, and the household's total desired income. SS income should be the combined expected household benefit.