Retirement Calculator

How to Use the Retirement Calculator

This retirement calculator projects how your savings could grow between today and the age you plan to stop working, then optionally turns that projection into a rough monthly income using a withdrawal rate. Everything is calculated instantly in your browser, so you can test different assumptions without sharing any personal data.

1. Enter your current age and your planned retirement age. The difference between the two sets the time horizon, in years, over which your savings can grow. Example: a 30-year-old planning to retire at 65 has a 35-year horizon, or 420 monthly periods.

2. Add your current savings and your monthly contribution. Type the amount you have already saved and the amount you expect to add each month. Example: starting with $10,000 and adding $300 a month builds a steady stream of deposits throughout the projection.

3. Set an expected annual return. This is the average yearly growth you want to assume, entered as a percentage. The calculator applies it as a constant monthly rate and compounds it. Example: a 7% annual return becomes roughly 0.583% per month.

4. Read the projection and the optional income estimate. The results show the projected balance at retirement, the total you contributed, the estimated investment growth and the number of years to retirement. If you switch on the withdrawal estimate, the calculator applies your chosen rate (4% by default) to suggest a possible monthly income. Use the copy button to keep the summary.

What Does This Retirement Calculator Estimate?

The calculator uses the future value of an annuity formula. It grows your current savings with compound interest and adds the future value of a series of equal monthly contributions: FV = P x (1 + r)^n + C x ((1 + r)^n − 1) / r, where P is your current savings, C is the monthly contribution, r is the monthly rate of return and n is the number of months until retirement. When the assumed return is zero, the projection is simply your current savings plus every contribution you make. The optional income figure applies a withdrawal rate to the projected balance. The well-known 4% rule divides the balance into an annual income of about 4% of the total, then splits that into monthly amounts. For example, a projected balance of $1,000,000 would suggest an annual income near $40,000, or roughly $3,333 a month before taxes. The rule is a planning shortcut, not a promise: markets vary, and a real portfolio may last longer or shorter than the rule assumes. Every number shown here is an estimate built on the assumptions you type in. A constant annual return never happens in reality — some years are far better and some are negative. The projection ignores inflation, taxes, fees and any change in your contribution over time, all of which can substantially change the outcome. Treat the result as a starting point for your own planning and speak with a qualified professional before making decisions.

Common Applications

1. Testing the effect of saving more. Raising a monthly contribution from $300 to $500 over a 35-year horizon at an assumed 7% return adds hundreds of thousands of dollars to the projected balance, showing how small monthly changes compound.

2. Comparing retirement ages. Running the same savings at age 60 instead of 65 removes five years of contributions and growth. Seeing the gap makes the cost of retiring early concrete.

3. Judging the impact of returns. A 4% assumed return instead of 7% produces a dramatically smaller projection, which is why cautious assumptions matter when planning.

4. Setting a savings goal. Working backwards from a target balance, you can estimate roughly what monthly contribution would be needed to reach it by a chosen age.

5. Estimating possible income. Applying the 4% rule to the projected balance gives a rough monthly income to compare against expected living costs in retirement.

Why Compound Growth Does the Heavy Lifting

The most striking feature of any retirement projection is how the balance curve bends upward in the final years. Early on, the growth looks modest because the balance is small and contributions dominate. As the years pass, the balance itself starts generating meaningful returns, and those returns begin to earn returns of their own.

This is why time is the most valuable ingredient you have. Someone who starts saving at 25 and someone who starts at 40 can make identical monthly contributions, yet the earlier saver can end up with a much larger balance purely because the money had more years to compound. The middle columns of the projected balance table make this visible: watch the growth column pull ahead of the contributed column as the horizon lengthens.

How Cautious Assumptions Protect Your Plan

A retirement projection is only as good as the assumptions behind it, and the return assumption is the most sensitive of all. A few percentage points sounds small, but over three or four decades it changes the result enormously. For that reason many planners prefer to model several scenarios — a cautious rate, a middle rate and an optimistic rate — and check that the plan still works in the cautious one.

It also helps to remember what the projection leaves out. Inflation reduces what a future balance can buy, investment fees quietly take a slice each year, and taxes reduce the income you can actually spend. Building a buffer for all three makes a projection more realistic. The calculator gives you a clear, fast way to explore assumptions; the judgement about which assumptions are safe is yours and, ideally, your adviser's.

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