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Learn long-term investing with clarity.

Simple, practical guides that explain the ideas behind Rionux tools: compounding, inflation, portfolio allocation, risk, and long-term decision making.

Foundations

The two forces behind every long-term result: growth that compounds on itself, and inflation that quietly works against it. Read these first if you read nothing else.

6 min readHow Compound Interest Works: A Beginner's GuideWhy time matters more than the return rate, and how to put consistent long-term investing to work in your favour — with scenarios you can run yourself.

7 min readSimple Interest vs Compound Interest: What's the Difference?Simple interest is calculated only on your original principal; compound interest is calculated on the principal plus the interest already earned, so it grows faster over time. A neutral, worked-example guide.

5 min readWhy Inflation MattersWhy long-term investors judge returns after inflation, what that does to a plan built on nominal numbers, and how to think about staying ahead of it.

Understanding what you actually earned

Performance can be reported several honest ways, and they disagree. These guides untangle total versus annual, price versus income, and nominal versus after-inflation — so you can tell whether two figures are even comparable.

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 ReturnTotal 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 DifferAveraging yearly returns overstates real growth because of volatility drag. CAGR is the compounded rate that matches your ending balance.

8 min readCAGR vs IRR (and XIRR): What's the Difference?CAGR assumes one lump sum growing at a smooth annual rate; IRR (and its spreadsheet form XIRR) accounts for money added and withdrawn at different times. A neutral, worked-example guide to which return measure fits which situation.

6 min readReal Return vs Nominal ReturnNominal return is the raw percentage earned; real return subtracts inflation to show the change in purchasing power. With the Fisher equation.

Structuring a portfolio

How much risk to take, how widely to spread it, and which wrapper to hold it in. These cover the choices that shape how a portfolio behaves in both good and bad markets.

7 min readHow to Choose Your Portfolio AllocationHow to decide the mix of stocks, bonds, and cash that fits your time horizon and tolerance for risk — with the trade-offs behind each choice.

7 min readAsset Allocation vs DiversificationAsset 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 ThumbHow 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.

Investing consistently and earning income

When to put money in, and what to do with the income it produces. Both are decisions with real trade-offs rather than a single correct answer.

7 min readIs Dollar-Cost Averaging Right for You?How to judge whether investing a fixed amount on a schedule suits your situation — where it helps, where it falls short, and the trade-offs to weigh.

8 min readLump Sum vs Dollar-Cost Averaging: How They CompareInvesting 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 readDividend Yield vs Dividend GrowthDividend yield is the income a stock pays now; dividend growth is how fast that payment rises. The tradeoff, and how reinvestment changes it.

Planning financial independence

The milestones and withdrawal assumptions behind FIRE. These guides separate the point where growth alone can finish the job from the point where a portfolio can fund your life — and compare the rates used to draw it down.

7 min readFIRE vs Coast FIRE: What's the Difference?Full FIRE means enough invested to live off withdrawals now; Coast FIRE means enough invested that growth alone reaches your number by retirement age, so you only cover today's expenses. A neutral, worked-example guide.

7 min readCoast FIRE vs Barista FIRE: What's the Difference?Coast FIRE means your invested balance can grow to your retirement number on its own, so you only cover today's expenses. Barista FIRE means you semi-retire and cover part of your expenses with part-time income. A neutral, worked-example guide.

7 min read3.5% vs 4% Withdrawal Rate: How They CompareThe 4% rule and a more conservative 3.5% rate set how much you withdraw from a portfolio each year. See what a lower rate changes for income and resilience, under stated assumptions, with a neutral worked example.

How to use these guides

Rionux is built in three layers, and knowing which one you need saves time. The glossary defines concepts: what total return is, how CAGR is calculated, what correlation measures. The guides on this page do something different — they help you decide between two reasonable options. And the calculators let you settle the question with your own numbers instead of someone else's example.

Most questions in investing are not really definitional. You rarely need to know only what dollar-cost averaging means; you need to know whether it suits the money you have and the horizon you are working with. That is what a guide is for. Each one lays out a genuine trade-off, works through the arithmetic with real figures, and ends at the calculator that shows you your own case.

None of these guides recommends a course of action, and none of them declares a winner. Every number here holds under a stated set of assumptions, and those assumptions are always visible so you can change them. Where two approaches genuinely differ by situation — and most do — the guide says so plainly rather than manufacturing a verdict.

Start with the concept
If a term is unfamiliar, read its glossary entry first. Each one defines the idea in a sentence, shows the formula where there is one, and includes a small interactive example.
Browse the glossary
Then read the decision
The guides below compare the options a long-term investor actually weighs — lump sum against a schedule, yield against growth, one allocation rule against another — neutrally, with the trade-offs stated.
Read the guides
Then run your own numbers
Every guide ends at a calculator. Change the return assumption, the horizon, or the contribution and watch which way the comparison tips for your situation rather than the example's.
Open the calculators