Question 1

What does $500 grow to at 8% for 15 years?

Accepted Answer

$500 invested at 8% annual compound interest for 15 years grows to $1,586. Your original investment earns $1,086 in interest — a 217.2% total return and a 3.17× multiplier on your money.

Question 2

How long does it take to double money at 8%?

Accepted Answer

At 8% annual compound interest, your money doubles approximately every 9 years (the Rule of 72: 72 ÷ 8 = 9). Over 15 years, $500 has the potential to double 1.7 times.

Question 3

Is 8% a realistic return?

Accepted Answer

8% is a moderate return that aligns with long-term historical averages for diversified share portfolios. The ASX 200 has returned around 9–10% p.a. including dividends historically, so 8% is realistic over long periods after accounting for fees and portfolio mix.

Question 4

What's the effect of adding regular contributions?

Accepted Answer

These figures show a one-time lump sum of $500 with no additional contributions. Adding regular contributions compounds the growth dramatically. For example, adding $200/month to $500 at 8% for 15 years would result in a significantly larger final balance. Use the interactive calculator above to model your own contribution amount.

Question 5

How does inflation affect this result?

Accepted Answer

This calculator shows nominal returns — the dollar figures before adjusting for inflation. Australia's historical inflation rate is around 2–3% per year. To estimate real purchasing power, subtract the inflation rate from your return: at 8% return and 2.5% inflation, your real return is approximately 5.5% p.a. In real terms, $1,586 in 15 years would buy meaningfully less than it does today.

Year	Balance	Interest
Yr 1	$540	+$40
Yr 2	$583	+$43
Yr 3	$630	+$47
Yr 4	$680	+$50
Yr 5	$735	+$54
Yr 6	$793	+$59
Yr 7	$857	+$63
Yr 8	$925	+$69
Yr 9	$1,000	+$74
Yr 10	$1,079	+$80
Yr 11	$1,166	+$86
Yr 12	$1,259	+$93
Yr 13	$1,360	+$101
Yr 14	$1,469	+$109
Yr 15	$1,586	+$117

Rate	Final balance	Interest earned	Multiplier
4%	$900	$400	1.80×
5%	$1,039	$539	2.08×
6%	$1,198	$698	2.40×
7%	$1,380	$880	2.76×
8% ◀	$1,586	$1,086	3.17×
9%	$1,821	$1,321	3.64×
10%	$2,089	$1,589	4.18×

Year	Balance	Interest this year	Total interest	Growth
Year 1	$540	+$40	$40	1.08×
Year 2	$583	+$43	$83	1.17×
Year 3	$630	+$47	$130	1.26×
Year 4	$680	+$50	$180	1.36×
Year 5	$735	+$54	$235	1.47×
Year 6	$793	+$59	$293	1.59×
Year 7	$857	+$63	$357	1.71×
Year 8	$925	+$69	$425	1.85×
Year 9	$1,000	+$74	$500	2.00×
Year 10	$1,079	+$80	$579	2.16×
Year 11	$1,166	+$86	$666	2.33×
Year 12	$1,259	+$93	$759	2.52×
Year 13	$1,360	+$101	$860	2.72×
Year 14	$1,469	+$109	$969	2.94×
Year 15	$1,586	+$117	$1,086	3.17×

Year	Balance	Interest
Yr 1	$540	+$40
Yr 2	$583	+$43
Yr 3	$630	+$47
Yr 4	$680	+$50
Yr 5	$735	+$54
Yr 6	$793	+$59
Yr 7	$857	+$63
Yr 8	$925	+$69
Yr 9	$1,000	+$74
Yr 10	$1,079	+$80
Yr 11	$1,166	+$86
Yr 12	$1,259	+$93
Yr 13	$1,360	+$101
Yr 14	$1,469	+$109
Yr 15	$1,586	+$117

$500 at 8% for 15 Years

How $500 grows at 8%

Year-by-year projection

Growth chart

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