Find out when you will hit your savings target at your current contribution rate.
Illustrative projections only. Not financial advice. Returns are not guaranteed.
The millionaire date calculator is built on the compound interest formula: FV = P(1 + r/n)^(nt) + PMT × [(1 + r/n)^(nt) - 1] / (r/n). Where FV is future value, P is starting principal, r is annual interest rate, n is compounding frequency, t is time in years, and PMT is regular contribution. The result shows how quickly money grows when returns are reinvested — the core mechanic of long-term wealth accumulation.
Compound interest produces a counterintuitive result: starting amount has a disproportionate impact on final value because it benefits from more years of compounding. A £10,000 lump sum invested at 7% for 30 years grows to approximately £76,000 with no further contributions. Monthly £100 contributions over the same 30 years at 7% produce approximately £121,000. The lump sum is nearly three-quarters as valuable despite being a fraction of the total contributions — purely because of early compounding.
This is the mathematical basis for the financial planning maxim "time in market beats timing the market." Starting with a small amount early is worth significantly more than starting with a large amount late.
A 7% nominal annual return is commonly used in personal finance projections because it approximates the long-run historical average return of diversified global equity index funds after inflation adjustment. The actual historical figure for a 60/40 portfolio (60% global equities, 40% bonds) over rolling 30-year periods has ranged from roughly 4% to 10% depending on the start date. 7% is an optimistic but defensible centre estimate — not a guarantee.
In most countries, the most efficient path to investment growth uses tax-advantaged accounts — ISAs (UK), 401(k) and IRA (US), superannuation (Australia), RRSP and TFSA (Canada) — before investing in taxable accounts. Tax drag on investment returns compounds significantly over decades. A 7% return taxed annually at 20% produces approximately 5.6% net, which over 30 years is a substantial difference in outcomes.
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