Investment Calculator

An investment calculator projects how a pot of money grows over time when you add to it regularly and it earns a return. You enter a starting balance, a monthly contribution, an expected annual return, and a time horizon, and it works out the future value, how much of that is your own money versus growth, and what the balance is worth after inflation. This one goes further than a plain growth tool: it shows the inflation-adjusted 'real' value beside the headline number and can solve the monthly amount you need to reach a target.

Nominal value is the raw future balance, the dollar figure your account would actually show. Real value strips out inflation, so it tells you what that balance buys in today's money. A $500,000 balance in 25 years sounds large, but at 3% inflation it buys what about $240,000 buys now. That gap is why the calculator shows both: the nominal number motivates, and the real number keeps the plan honest. Your 401k might hit a big figure, yet the real value is the one that answers whether it actually gets you there.

Switch to goal mode and enter the target, your starting balance, the expected return, and the years you have. The calculator runs the future-value math in reverse and returns the monthly contribution that lands you on the target. It also shows what that goal is worth in today's dollars, so you can decide whether the target itself should be higher to keep its purchasing power. Change the return or the time horizon and the required monthly updates instantly.

Use a rate you can defend, not a hopeful one. A broad stock index has historically averaged around 7% a year after inflation over long periods, or roughly 10% before inflation, though any single decade can be far higher or lower. A balanced mix of stocks and bonds sits lower, and cash lower still. Because the return drives the result more than any other input, it is worth running a cautious rate and an optimistic one to see the range rather than betting on one number.

No, and that is deliberate, because tax treatment depends on the account. Money in a Roth grows and comes out tax-free, a traditional 401k or IRA is taxed on withdrawal, and a taxable brokerage owes tax on gains and dividends along the way. Fund fees also quietly lower your real return. Treat the return you enter as your net-of-fee expected return, and remember the nominal figure is before any tax due at withdrawal. It is a planning estimate, not tax or investment advice.

It raises your monthly contribution by a set percentage each year, which mirrors how people usually invest more as their pay grows. Setting it to 3% means a $500 monthly contribution becomes about $515 in year two, $530 in year three, and so on. Even a small yearly bump makes a large difference over decades because each raised contribution gets its own runway to compound. Leave it at 0 for a flat contribution the whole way through.

They share the same growth engine, but the focus differs. A compound interest calculator centers on how interest builds on itself at a chosen compounding frequency. This investment calculator is built around a real-life plan: it foregrounds inflation-adjusted value, an annual contribution increase, and a goal-solving mode for questions like 'what monthly gets me to a million.' If you just want to see interest-on-interest, the compound interest calculator is simpler; for retirement-style planning with inflation and a target, this is the fuller tool.