InvestKit is a set of ten free calculators for the decisions that actually build wealth: how much to save for retirement, whether your 401(k) match is fully captured, what inflation quietly does to your money, and the exact number that makes work optional. No sign-up, no spreadsheets — just clear answers in seconds.
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Tell it where you are today and what you can set aside each month, and it projects the balance waiting for you at retirement — plus how much of that pile is your own contributions and how much is investment growth doing the heavy lifting.
See where your workplace plan could end up — and exactly how much free employer match money you capture each year, or leave on the table if you contribute too little.
Same money, two very different tax stories. Compare the after-tax value of each account side by side — the winner usually comes down to one question: is your tax rate higher now, or later?
How to read this: a Traditional IRA takes the full pre-tax amount and taxes it on the way out. A Roth takes what is left after today's tax and is never taxed again. Contribution limits, income rules and employer plans can change the picture — this is the pure tax-rate comparison.
Work the goal from either direction: pick a deadline and learn the monthly amount that gets you there, or pick a monthly amount and learn the date your goal is reached.
Inflation is a quiet tax on cash sitting still. See what something that costs a set amount today is likely to cost years from now — and what today's money will actually buy by then.
Banks advertise APR, but compounding quietly pays you a little more. Convert any APR to its true APY and see what a deposit actually earns in a year at each compounding frequency.
The gap between APR and APY looks small, but on large balances held for years it is real money — and it is why two accounts with the same headline rate can pay different amounts.
The oldest shortcut in investing: divide 72 by your annual return and you get roughly how many years it takes your money to double. This shows the famous estimate next to the exact answer — and runs the trick in reverse.
Why 72? It is a rounded stand-in for the math of compound growth (the natural log of 2, scaled for percentages), chosen because it divides neatly by 2, 3, 4, 6, 8, 9 and 12. The estimate is closest to exact for returns between about 5% and 10%.
Project the income stream from a dividend portfolio year by year. Enter what you have invested — or your share count and price — then add a yield and a dividend growth rate to see the paycheck your portfolio could write.
| Year | Annual income | Cumulative |
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Projection assumes the share price stays flat, so a growing payout steadily raises your yield on the original investment. Real prices move, and dividends are never guaranteed — companies can cut them.
A 1% fee sounds trivial. Over a few decades it can quietly swallow a six-figure slice of your future. Compare two fee levels on the same investment and see the true long-term cost of the expensive one.
Fees compound just like returns do — every dollar paid out in fees is a dollar that stops growing for you. It is one of the few parts of investing you can fully control.
Your FI number is the portfolio size that could cover your spending for good — roughly 25 times your annual expenses. Work yours out, then see your Coast FI target: the amount that could grow into the full number on its own.
The 25× rule comes from the 4% guideline: a portfolio about 25 times your yearly spending has historically stood a strong chance of lasting through retirement. Coast FI is the milestone where, in theory, you could stop contributing and let growth finish the job by retirement age.
InvestKit is part of the TapeToolHQ network of free, no-nonsense web tools. It exists for one reason: the most important money decisions — how much to save, which account to use, whether your fees are quietly eating your future — are usually just arithmetic wearing a scary costume. These ten calculators strip the costume off.
Every tool here runs entirely in your browser. Nothing you type is sent anywhere, stored, or shared, and there is no account to create. Type your real numbers, get a straight answer, and close the tab whenever you like.
The tools are built for savers and investors in the United States and other Western markets, using familiar ideas like the 401(k), Roth and Traditional IRAs, APY, and the 25× rule of financial independence. Figures are in US dollars, and you can change every assumption — return, tax rate, fees, time horizon — to match your own situation.
Questions, corrections, or an idea for the next calculator? Write to us at [email protected] — real emails get real replies.
Every projection on this page is a hypothetical example for education only. These calculators are not financial advice, and InvestKit is not a financial adviser, broker, or tax professional. Results assume the steady returns, tax rates, and inflation you enter — real markets are bumpier, rules change, and your situation has details no calculator can see. Past performance does not guarantee future results. For decisions that matter, talk to a qualified fiduciary adviser or tax professional who knows your full picture.