How the projection works
The calculator adds your monthly contribution at the end of each month and applies interest at one twelfth of the yearly return. This repeats for every month until your chosen retirement age. It is the standard future-value of a regular saving plan.
Two things drive the outcome: time and the amount saved. Because gains build on earlier gains, the early years matter more than people expect.
A worked example
Imagine you are 30, have 20,000 saved and add 500 a month until 65, earning 6% a year. After 35 years the balance is about 874,826. You will have paid in 230,000 yourself, so roughly 645,000 is growth.
With 2.5% inflation, that final figure is worth about 368,600 in today’s prices. At a 4% withdrawal rate that would support roughly 14,700 a year, or 1,230 a month, in today’s money, before tax.
What can change the answer
Starting five years later, saving a little less, or earning 1% less each year can reduce the final balance by tens of thousands. Try a few variations in the calculator to see how sensitive the result is.
Fees matter too. A 1% yearly fund fee on a long plan can take a large share of the growth. Compare charges when choosing an account or fund.
Limits of a simple projection
Markets rise and fall, and real returns are not steady. Rules for pensions, tax and allowances differ between countries. This tool is for planning and learning, not personal financial advice.
Questions people ask
How much will I have saved by retirement?
It depends on how much you start with, how much you add each month, the return you earn and how long you save. Starting with 20,000 and adding 500 a month at 6% for 35 years grows to about 874,800, of which 230,000 is money you paid in.
What return should I assume?
Nobody can know future returns. Many planners use a cautious figure well below recent stock-market highs, and test a few cases such as 4%, 6% and 8%. Remember that fees reduce what you actually earn.
Why show the result in today’s money?
Prices rise over time, so a large future sum buys less than it appears to. Dividing by cumulative inflation shows what the balance is worth in current purchasing power. In the example, 874,800 in 35 years is about 368,600 today at 2.5% inflation.
What is the 4% rule?
A rule of thumb that withdrawing about 4% of your savings in the first year of retirement, then adjusting for inflation, has historically lasted around 30 years in US data. It is not a guarantee and may not suit every country, period or retirement length.
Does this include pensions, tax or employer contributions?
No. Add employer matches to your monthly contribution if you want them included. State pensions, tax on withdrawals and account fees are not modelled, so treat the result as a simple projection.