Finance

Personal Future Value Monthly Savings Calculator (20 Years)

Estimate the future value of regular monthly savings. This personal version uses a 20-year planning term as its starting point.

The Future value result is the total amount your monthly deposits would grow to by the end of 20 years at the annual rate you entered, including interest earned along the way, so it will be higher than the sum of your deposits alone; it is a planning estimate, not a guaranteed balance, because the rate and the deposit pattern would need to stay unchanged.

Formula

Future value uses the monthly rate and the number of monthly deposits to grow each deposit with interest.

How it works

Each monthly deposit earns interest from the month it is made until the end of the term.

Worked example

Monthly deposit $500, annual rate 6%, term 20 years. First, the monthly rate is 6% divided by 12, which is 0.005, and the number of deposits is 20 times 12, which is 240. Using the future value formula, the future value is $500 times ((1.005 to the power of 240) minus 1) divided by 0.005, which is $231,020.45. Over 240 deposits you pay in $120,000.00, and interest adds $111,020.45, which is 48.1% of the future value.

Who this term suits for a person: A 20-year term suits a person saving through a full working-life block, for example starting at 25 for a pot at 45, funding two university funds, or building a mortgage-free fund. The $500 payment must survive promotions, children, house moves and slow years, so build a cash buffer first and restart quickly after any break rather than giving up the plan.

FAQs

How does monthly saving grow?
Regular deposits grow because each deposit earns interest, and that interest then earns more interest.

Is this personal calculator exact?
No, it is an estimate for planning only, based on the numbers you enter.

Are these figures financial advice?
No, they are estimates for planning only, not financial advice. Check with a qualified adviser for decisions involving large sums.

Why does interest pass $100,000 at 20 years?
Interest is $111,020.45 on deposits of $120,000, which is 48.1% of the $231,020.45 future value. The last 5 years alone add $85,611.09 of future value on only $30,000 of new deposits, because interest is now earned on the $145,409.36 pot built by year 15 as well as on new deposits.

Is 20 years too late to start if I am 40?
No. Starting at 40 gives a pot at 60 of $231,020.45 on these assumptions, which is still a large sum from $500 a month. Starting later still helps, but the monthly deposit needed for the same target rises sharply, so use the calculator with your own age and term instead of copying a 20-year figure.

Should saving come before clearing other debts?
Usually clear high-interest debt first. This calculator assumes no debts, fees or taxes, and a fixed 6% return, so if a debt charges more than 6%, paying it off beats saving at 6%. Compare your own debt rate with 6% before you commit $500 a month to saving.

Estimates only, not financial advice. Figures are approximate and do not include all fees, taxes, or changing rates unless stated.