Let time compound your wealth
A free online calculator for investment returns, recurring contributions, and long-term wealth growth.
Assets after 30 years
¥4,471,077
Principal
¥1.18M
Profit
¥3.29M
Annual
8.00%
Model long-term returns with clarity
Estimate lump-sum investing, recurring contributions, CAGR, and FIRE targets with one responsive model.
Scenario presets
Apply a preset annual return and refresh the model instantly.
Compound Interest Calculator
Compounding frequency
Final amount
¥5,594,459
Estimated ending portfolio
Total principal
¥1,180,000
Total profit
¥4,414,459
Total return
374.11%
Asset growth
Principal and profit
Principal vs investment profit
Example: invest 3,000 every month at 8% annually for 30 years
Assuming monthly compounding, total principal is ¥1,080,000 and the estimated final amount is ¥4,500,886.
Calculation guides
Each calculator shows the assumptions behind the result, so you can understand the model instead of only reading a number.
How to read compound growth
Compound models are useful for long-term investing, savings goals, and retirement planning. Results depend on annual return, time horizon, compounding frequency, and recurring contributions.
What DCA estimates
The DCA calculator treats each contribution as a separate cash flow and compounds it over the remaining period. It helps compare contribution amount, duration, and assumed return.
When CAGR helps
CAGR converts total growth over a period into a smoothed annual rate, making it easier to compare investments, business revenue, or portfolio values across different time spans.
FIRE targets are estimates
The FIRE model estimates years to target from expenses, withdrawal rate, current assets, and monthly investing. It should not replace cash-flow, tax, insurance, or market-risk planning.
Learn before you calculate
Read practical guides about compound interest, DCA, CAGR, FIRE planning, retirement assumptions, withdrawal rates, and calculator limitations before relying on any estimate.
Visit the learning centerFAQ
Plain-language answers for compound interest, DCA, CAGR, and FIRE assumptions.
What is compound interest?
Compound interest reinvests earned returns so both principal and accumulated gains can grow in future periods.
What is the compound interest formula?
A common lump-sum formula is FV = PV × (1 + r / n) ^ (n × t). With recurring investments, each cash flow is compounded period by period.
How are DCA returns calculated?
Dollar-cost averaging adds a fixed amount weekly, monthly, or quarterly, then compounds each contribution at the matching periodic return.
How do you calculate CAGR?
CAGR = (Ending Value / Beginning Value) ^ (1 / Years) - 1. It measures the smoothed annual growth rate over a period.
What does FIRE mean?
FIRE stands for Financial Independence, Retire Early. A common target is annual expenses divided by a safe withdrawal rate, often 4%.
Who is this calculator for?
It is useful for fund investing, index investing, retirement planning, education funding, FIRE planning, and long-term savings goals.