The Investment Return Calculator projects an investment's growth in two modes — regular contributions (SIP) or a single lump sum — with the adjustments most simple calculators skip: an annual step-up on contributions, tax drag on returns, annual fees, customizable compounding and contribution frequencies, and an inflation-adjusted "real" maturity value alongside the nominal one. A year-by-year table separates what you put in from what growth added.
How It Works
First, your headline return is converted into the effective annual rate the projection actually uses — the gross return reduced by your tax rate on returns, minus annual fees:
In lump sum mode the amount compounds at that rate: . In SIP mode the calculator simulates period by period: your starting amount plus contributions at your chosen frequency, each period growing the balance before the next deposit lands, with the contribution stepped up once a year by your step-up percentage. The real maturity value then deflates the result by your inflation rate: .
Worked Example 1: A Plain SIP
**60,000 and the projection reaches 31,473.02, a return multiple of 1.52×. Contributions dominate the early rows of the year table; by year ten, growth is adding more each year than it did in the first three years combined. That crossover is the visible signature of compounding.
Worked Example 2: What Tax and Fees Do to a Lump Sum
Invest **63,443.38. Now apply a 15% tax on returns and 1% annual fees: the effective rate becomes 8% × 0.85 − 1% = 5.8%, and the same investment reaches only **16,851, roughly a quarter of the outcome. Deflate at 3% inflation and the real value is 20,000 grew by about half, not the 2.3× the nominal figure advertises. Simple version for scale: 56,044.11, a 5.60× multiple — every point of drag avoided is worth more than a point of gross return chased.
Reading the Outputs
Return multiple (final value ÷ total invested) is the fastest summary: 1.52× means each dollar became $1.52. Total returns is the same story in dollars. The year rows matter for planning: they show when growth overtakes contributions — the point after which stopping contributions hurts less than stopping early would have — and they expose how much of a step-up plan's result depends on the later, larger contributions actually happening.
Limitations
The projection uses a constant effective return; markets deliver averages in a jagged order that changes results for anyone adding or withdrawing money along the way. Tax is modeled as a smooth annual drag on returns, which approximates an annually taxed account — it does not reproduce deferred capital-gains treatment, franking, or jurisdiction-specific rules, and the fee field is a flat annual percentage of returns setting, not a balance-based charge schedule. Contribution frequencies other than monthly are supported (the per-period contribution scales accordingly), but pay-day timing within periods is not modeled. Projections are arithmetic, not forecasts.
Frequently Asked Questions
What is the annual step-up for?
It models reality: most people's capacity to invest grows with their income. A 5 to 10% annual step-up on a SIP — contributions rising as salary does — typically adds more to the final value than a point of extra assumed return, and it does so without extra market risk. The year table shows the stepped contributions explicitly.
Why does the calculator reduce my return for tax before compounding?
Because that is the order in which the drag actually bites in an annually taxed environment: each year's growth is trimmed, and next year compounds the trimmed amount. Applying tax once at the end would understate the cost. If your account is tax-deferred or tax-free, set the tax rate to zero and the projection uses your gross return minus fees only.
SIP or lump sum — which projects higher?
Given the same total money and the same start date, the lump sum wins because all of it compounds from day one. The SIP exists because most people invest from income as it arrives; its step-up feature is what closes much of the gap over long horizons.