Investment projections, made transparent.
Model long-term investment outcomes with transparent formulas, inflation-adjusted views, and shareable projections. No account. No tracking.
Your plan
Calculations run in your browser. Inputs are not stored.
Illustrative assumptions only. Adjust the rate for your own model.
How often interest is credited to your balance — your monthly contribution stays the same.
Educational purposes only. Not financial advice. See the full methodology and disclaimer.
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Investment planning calculators
Every calculator is instant, transparent about its math, and shareable with a link.
Compound Interest
See how your balance grows year by year, and how much of it is growth, not your own money.
Open calculator →Dollar-Cost Averaging
Model steady monthly, biweekly or weekly investing and watch your contributions compound.
Open calculator →DCA vs Lump Sum
Same budget, same time, side by side. See exactly how much one strategy can beat the other.
Open calculator →Rule of 72
How long until your money doubles? The fastest mental shortcut in finance.
Open calculator →Savings Goal
Work backwards from a target amount to the monthly contribution you need.
Open calculator →Investment Return
Work backwards from your final balance to your real annualized return.
Open calculator →Retirement
Project your nest egg and how much you can safely withdraw each month.
Open calculator →FIRE Calculator
Find your FIRE number and how many years to financial independence.
Open calculator →Loan Payment
See your equal monthly payment, total interest and total cost of any loan.
Open calculator →Inflation
See what your cash will really be worth — and how much buying power inflation takes.
Open calculator →Portfolio Growth
See contributions, growth and fees separately — and what fees cost you over decades.
Open calculator →ETF Fee Impact
Compare two ETFs and see what a small expense ratio gap costs you over decades.
Open calculator →Net Worth
Everything you own minus what you owe — your true financial position.
Open calculator →Coast FIRE
The lump sum you need today so compounding can finish the job.
Open calculator →4% Rule
Find the portfolio you need to support your retirement spending.
Open calculator →Transparent math
Every calculator shows its formula and assumptions. No black boxes.
No sign-up
Open the page and calculate. No accounts, no email walls.
No data stored
Everything runs in your browser. Your numbers never leave your device.
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Learn before you calculate
Short, plain-English explanations of the math behind the tools.
The same amount, on a schedule, no matter the market→ How Long to Double Your Money
The Rule of 72, in one line→ Is $500 a Month Enough to Invest?
What $500 a month actually builds→ What $500 a Month Grows To in 30 Years
A full working career of $500 a month→ What Is Coast FIRE?
The point where compounding can finish the job→ How to Grow $10,000 to $100,000
Compounding alone vs compounding plus contributions→ Can You Retire on $1 Million?
The withdrawal-rate check that decides it→ What $10,000 Could Grow To
One lump sum, four horizons→ How to Reach $1 Million
What monthly savings, returns and time really add up to→ What $100 a Month Grows To in 20 Years
Small contributions, big compounding curve→ How Does Inflation Affect Your Savings?
Why cash quietly loses buying power→ How to Save $10,000 in a Year
$833 a month is a plan, not a personality trait→ VOO vs VTI: Which Should You Choose?
Same fee, same philosophy — different slices of the market→ Debt Snowball vs Avalanche
Two ways to pay off debt — one wins on math, one on momentum→ ETF vs Mutual Fund: What's the Difference?
How they trade, what they cost — and where fees compound→ The Compound Interest Formula, Explained
A = P(1 + r/n)^(nt), broken down step by step→ How Compound Interest Works
The 3 variables that decide your outcome→ What Happens If You Invest $500 a Month for 10 Years?
Run the numbers on steady monthly investing→ DCA vs Lump Sum: Which Is Better?
What the math says, and what it doesn't capture→ Monthly vs Daily Compound Interest
How much compounding frequency really matters→ How Much to Save Each Month to Reach a Goal
Work backwards from any target to your monthly number→ What's My Real Investment Return?
The honest way to judge how your money actually performed→ How Much Do I Need to Retire?
The two numbers that make a retirement plan→ Understanding Your Loan Payment
Why early payments are mostly interest — and how term changes cost→