What This Calculator Does

"How much will I actually have by the time I retire?" is a simpler question than most retirement planning tools treat it as, and this calculator answers just that part of it directly. Give it your current age, the age you plan to retire, what you've already saved, how much you'll add every year, and the growth rate you expect, and it projects your balance the year you retire, along with how much of it came from your own contributions versus investment growth. It also turns that balance into a rough monthly income estimate, and lets you add your own Social Security or pension estimate on top to get a fuller monthly income picture.

How to Use It

Enter Current Age and Retirement Age (the calculator needs the second to be later than the first, since it's projecting forward), then Current Savings, Annual Contribution, and Annual Growth Rate. The last field, Estimated Monthly Social Security/Pension, is optional — leave it at 0 if you'd rather see the savings projection on its own. Click Calculate and the Retirement Projection panel shows your projected Balance at Retirement, Years to Retirement, Total Contributions over that span, and Total Interest Earned, followed by an Estimated Monthly Income panel: your projected income from savings (using the common 4% withdrawal rule), your own SS/pension estimate, and the two added together as a Total Estimated Monthly Income. That total isn't a calculated benefit — the SS/pension portion is exactly whatever number you typed in, with no government formula applied to it.

The Formula

Each year runs the same two-step recurrence: first your annual contribution is added to the current balance, then the whole balance — savings plus that year's contribution — is grown by the annual rate. In other words, B = (B + contribution) × (1 + rate), repeated once per year for every year between your current age and your retirement age. Because the contribution is added before growth is applied each year, it earns a full year of growth in the very year it's made, rather than being tacked on at the end with no growth of its own.

The Estimated Monthly Income figures are a separate calculation layered on afterward — they never feed back into the balance projection above. Income from savings = Balance at Retirement × 4% ÷ 12 (the standard 4% annual withdrawal rule, converted to a monthly figure). Total Estimated Monthly Income = that number + your own monthly Social Security/Pension estimate, added exactly as entered with no adjustment or calculation applied to it.

A Worked Example

Someone who is 30 years old, plans to retire at 35, has $10,000 saved already, adds $5,000 a year, and expects 7% annual growth would see the balance evolve like this: year 1 takes ($10,000 + $5,000) × 1.07 = $16,050.00; year 2 takes ($16,050 + $5,000) × 1.07 = $22,553.50; and so on for five years total. By the end of year 5, the projected Balance at Retirement is $44,791.97. Total Contributions over those five years come to exactly $25,000 (five payments of $5,000), which means the remaining $9,791.97 of the final balance was earned purely through growth on the account.

From that same $44,791.97 balance, the 4% rule gives an Estimated Monthly Income from Savings of $149.31 ($44,791.97 × 4% ÷ 12). If that same person also enters $2,000 as their own Social Security/pension estimate, the Total Estimated Monthly Income becomes $2,149.31 — $149.31 from savings plus the $2,000 they typed in directly, unchanged.