Question 1

What does $100,000 grow to at 8% for 15 years?

Accepted Answer

$100,000 invested at 8% annual compound interest for 15 years grows to $317,217. Your original investment earns $217,217 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, $100,000 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 $100,000 with no additional contributions. Adding regular contributions compounds the growth dramatically. For example, adding $200/month to $100,000 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, $317,217 in 15 years would buy meaningfully less than it does today.

Year	Balance	Interest
Yr 1	$108,000	+$8,000
Yr 2	$116,640	+$8,640
Yr 3	$125,971	+$9,331
Yr 4	$136,049	+$10,078
Yr 5	$146,933	+$10,884
Yr 6	$158,687	+$11,755
Yr 7	$171,382	+$12,695
Yr 8	$185,093	+$13,711
Yr 9	$199,900	+$14,807
Yr 10	$215,892	+$15,992
Yr 11	$233,164	+$17,271
Yr 12	$251,817	+$18,653
Yr 13	$271,962	+$20,145
Yr 14	$293,719	+$21,757
Yr 15	$317,217	+$23,498

Rate	Final balance	Interest earned	Multiplier
4%	$180,094	$80,094	1.80×
5%	$207,893	$107,893	2.08×
6%	$239,656	$139,656	2.40×
7%	$275,903	$175,903	2.76×
8% ◀	$317,217	$217,217	3.17×
9%	$364,248	$264,248	3.64×
10%	$417,725	$317,725	4.18×

Year	Balance	Interest this year	Total interest	Growth
Year 1	$108,000	+$8,000	$8,000	1.08×
Year 2	$116,640	+$8,640	$16,640	1.17×
Year 3	$125,971	+$9,331	$25,971	1.26×
Year 4	$136,049	+$10,078	$36,049	1.36×
Year 5	$146,933	+$10,884	$46,933	1.47×
Year 6	$158,687	+$11,755	$58,687	1.59×
Year 7	$171,382	+$12,695	$71,382	1.71×
Year 8	$185,093	+$13,711	$85,093	1.85×
Year 9	$199,900	+$14,807	$99,900	2.00×
Year 10	$215,892	+$15,992	$115,892	2.16×
Year 11	$233,164	+$17,271	$133,164	2.33×
Year 12	$251,817	+$18,653	$151,817	2.52×
Year 13	$271,962	+$20,145	$171,962	2.72×
Year 14	$293,719	+$21,757	$193,719	2.94×
Year 15	$317,217	+$23,498	$217,217	3.17×

Year	Balance	Interest
Yr 1	$108,000	+$8,000
Yr 2	$116,640	+$8,640
Yr 3	$125,971	+$9,331
Yr 4	$136,049	+$10,078
Yr 5	$146,933	+$10,884
Yr 6	$158,687	+$11,755
Yr 7	$171,382	+$12,695
Yr 8	$185,093	+$13,711
Yr 9	$199,900	+$14,807
Yr 10	$215,892	+$15,992
Yr 11	$233,164	+$17,271
Yr 12	$251,817	+$18,653
Yr 13	$271,962	+$20,145
Yr 14	$293,719	+$21,757
Yr 15	$317,217	+$23,498

$100,000 at 8% for 15 Years

How $100,000 grows at 8%

Year-by-year projection

Growth chart

Frequently asked questions

Explore other scenarios

Related calculators