Lump Sum Investment Calculator
Got a bonus, tax refund, or a bit of savings sitting idle? See exactly what it could grow into if you invested it today, all at once, instead of letting it sit in a regular account.
What a lump sum investment actually is
Think of the difference between two ways of saving for something: dropping in a little money every month, versus putting in one big chunk all at once and leaving it alone. That second approach — investing a bonus, a tax refund, an inheritance, or savings you’ve built up, all in one go — is a lump sum investment. It’s common whenever money arrives in one piece rather than a steady paycheck.
The advantage is simple: your entire amount starts growing from day one, instead of slowly building up bit by bit. The tradeoff is that all your money enters the market at a single point in time, so timing matters more than it does when you’re investing gradually.
FV = future value, what your money grows into · P = the lump sum you’re putting inr = expected annual return, written as a decimal (8% becomes 0.08) · n = number of years invested
Why timing matters more here than with monthly investing
Because a lump sum enters all at once, when you invest it matters more than it would if you were spreading contributions out monthly. The flip side is the chart above: even a short delay in getting started costs you real money, because you lose those early years of growth compounding on your full amount. This is why “I’ll invest it once things settle down” often ends up more expensive than it sounds — the delay itself has a price.
Frequently asked questions
Neither is universally better. A lump sum tends to perform well when markets are trending upward, since your full amount is growing the whole time. Investing gradually can feel less stressful and reduces the risk of putting a large amount in right before a downturn.
It depends entirely on where you’re investing — some funds or platforms allow small amounts, others set higher minimums. Check the specific investment option you’re considering.
Usually yes, but withdrawing early may mean missing out on further growth, and some investments charge an early exit fee. Always check the specific terms before committing funds.
This shows an estimate assuming a perfectly steady annual return, which real investments never actually deliver. Use it to compare scenarios and understand the general shape of growth, not as a guaranteed outcome.
Want to see what regular monthly contributions would add on top?
Try the Dividend Yield Calculator next.
Dividend Yield Calculator Back to Toolkit