Tools
Investing tools for long-term clarity.
Find the right tool for where you are — growing your investments, building a portfolio, or planning financial independence.
Start here
A suggested path
New to Rionux? Start with compounding, then explore portfolio allocation, financial independence, and investment timing.
Grow my investments
Explore how time, contributions, return assumptions, and investing schedule can affect long-term growth.
Compound Interest Calculator
Understand how time, contributions, returns, and inflation shape long-term wealth.
Dollar Cost Averaging Calculator
Compare investing all at once with spreading the same amount over time.
Dividend Reinvestment Calculator
Project how reinvested dividends can compound into a growing income stream.
Total Return Calculator
See your complete return from price gains plus income like dividends, and what it works out to per year.
ROI Calculator
Work out your return on investment from what you put in and got back, and what it works out to per year.
Build my portfolio
Understand how different asset mixes shape expected return, concentration, and long-term outcomes — and what it takes to keep them on target.
Portfolio Allocation Calculator
Split your money across assets and see your weighted return, concentration, and long-term growth after inflation.
Portfolio Rebalancing Calculator
Compare your current mix against a target allocation and estimate what to buy or sell to rebalance.
Plan financial independence
Estimate how portfolio value, expenses, savings, returns, inflation, and withdrawal assumptions affect your path to FI.
FIRE Calculator
Estimate how much you need and when financial independence becomes possible.
Coast FIRE Calculator
See when your current investments could grow to support independence without adding more.
Retirement Calculator
Estimate your retirement balance and income from savings, contributions, returns, and inflation.
Safe Withdrawal Rate Calculator
Explore how different withdrawal rates affect how long a portfolio could last.
Understand inflation
See how inflation reduces purchasing power over time — the force behind every long-term calculator.
Inflation Calculator
Translate future money into today's purchasing power and see what inflation quietly costs.
Compare
Decide between two approaches
Neutral, side-by-side guides for the questions a single calculator can't settle on its own — each one embeds the tool that shows you your own case.
Lump Sum vs Dollar-Cost Averaging: How They Compare
Investing a lump sum all at once versus spreading the same amount over time: the trade-offs, a worked example, and what the evidence shows.
7 min readROI vs CAGR: What's the Difference?
ROI measures the total percentage gain; CAGR measures annualized growth. Why they differ, a worked example, and when each is the right lens.
6 min readTotal Return vs Price Return
Total return counts price change plus dividends reinvested; price return counts only price. How the two differ and when each is used.
7 min readCAGR vs Average Annual Return: Why They Differ
Averaging yearly returns overstates real growth because of volatility drag. CAGR is the compounded rate that matches your ending balance.
6 min readReal Return vs Nominal Return
Nominal return is the raw percentage earned; real return subtracts inflation to show the change in purchasing power. With the Fisher equation.
7 min readDividend Yield vs Dividend Growth
Dividend yield is the income a stock pays now; dividend growth is how fast that payment rises. The tradeoff, and how reinvestment changes it.
7 min readAsset Allocation vs Diversification
Asset allocation is how you split money across asset classes; diversification is how widely you spread risk within them. How the two work together.
8 min readPortfolio Allocation by Age: Rules of Thumb
How age-based rules of thumb — 60/40 and '100/110/120 minus age' — frame stock and bond splits. Explained as conventions, not recommendations.
7 min readIndex Fund vs ETF: What's the Difference?
An index fund is a strategy that tracks an index; an ETF is a structure that trades like a stock. How they relate and where they genuinely differ.
Roadmap
Coming next
Tools we're planning. They're marked Planned and aren't available yet.