Investing & Savings Guides
Everything you need to start investing, grow long-term wealth, and make compound interest work for you — written for normal people, not finance nerds.
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Open calculatorBeginner Guides
Start here if you're new to the topic.How Compound Interest Works
The mechanics of compounding explained in plain English — with charts and examples.
Read guideThe Compound Interest Formula
A=P(1+r/n)^(nt) — broken down step by step with realistic worked examples.
Read guideSimple vs Compound Interest
When each applies, how the math differs, and why compounding wins long-term.
Read guideHow Much Should I Save Each Month?
Benchmarks by income and goal — plus a quick formula you can apply tonight.
Read guideWhat's the Best Age to Start Investing?
The best age to start investing is the age you are right now. See exactly how much earlier starters end up with — the numbers are wild.
Read guideMost Popular
The guides readers reference most.How Much Will $100 a Month Grow To?
See how $100 a month grows over 10, 20, and 30 years at different interest rates — with realistic examples and a free compound interest calculator.
Read guideHow Much Will $500 a Month Grow To?
See how $500/month grows over 10, 20, and 30 years at 4%, 7%, and 10% returns — with examples and a free compound interest calculator.
Read guideHow Much Will $1,000 a Month Grow To?
See exactly how $1,000 a month grows over 10, 20, and 30 years at different rates — with realistic numbers and a free compound interest calculator.
Read guideHow Long Does It Take to Reach $1 Million?
See exactly how long it takes to save $1 million at different monthly amounts and return rates — with realistic timelines and a free calculator.
Read guideWhy Starting Early Matters More Than Amount
Two friends, two saving strategies — see why the one who started 10 years earlier ends up with more, even after contributing less.
Read guideRoth IRA vs Traditional IRA: Which One Wins?
Roth IRAs give tax-free retirement income; Traditional IRAs give a tax break today. Here's exactly which one to choose based on your situation.
Read guideAll Guides in This Topic
38 total guides7 Best Compound Interest Examples (with Real Numbers)
Seven real-world compound interest examples showing exactly how money grows over time — with side-by-side comparisons.
Read guideBeginner's Guide to Investing Consistently
How to start investing as a beginner: account types, what to buy, how to automate, and why consistency beats timing the market.
Read guideBest Compound Interest Strategy for Beginners
A simple, proven compound interest strategy for beginners: automate, invest in index funds, reinvest, and let time do the heavy lifting.
Read guideBest Interest Rate Assumptions to Use
What return rate should you use when projecting savings, retirement, or investments? Realistic ranges for stocks, bonds, savings, and mixed portfolios.
Read guideBest Savings Rate by Income (How Much to Save)
What percentage of your income should you save? Recommended savings rates by income level, age, and goal.
Read guideCan You Retire With $1 Million?
Is $1 million enough to retire? See how long it lasts, the 4% rule math, and realistic scenarios by lifestyle and retirement age.
Read guideCompound Interest: Monthly vs Yearly
Compounding frequency matters less than you'd think. See the real difference between monthly, yearly, and daily compounding with examples.
Read guideEmergency Fund: How Much Should You Save?
How big should your emergency fund be? Clear targets by life stage, where to keep it, and how to build it fast.
Read guideETF vs Mutual Fund Explained
ETFs vs mutual funds — the real differences in cost, taxes, trading, and minimums. Which one is better for long-term investing?
Read guideHow Inflation Affects Your Savings
Inflation quietly erodes the value of money sitting in low-interest accounts. See how much purchasing power you lose — and how to protect against it.
Read guideHow Long Does It Take to Double Your Money?
Use the Rule of 72 to figure out how long it takes to double your money at any return rate — with examples and a free calculator.
Read guideHow Long Does It Take to Save $10,000?
Timelines for hitting $10K at different monthly contribution amounts.
Read guideHow Much Do You Need to Retire at 60?
Retiring at 60 typically requires $1.2M–$2M depending on spending. See the full math, healthcare gap, and Social Security timing trade-offs.
Read guideHow Much Do You Need to Retire at 65?
Retiring at 65 typically requires 25× your annual spending — about $1M–$1.5M for most households. See the full math and Social Security impact.
Read guideHow Much Money Do You Need to Retire?
How much money do you actually need to retire? Use the 25× rule, 4% rule, and three realistic retirement scenarios.
Read guideHow Much Should I Save by Age 30?
Common savings benchmarks by age 30, how to catch up if you're behind, and a step-by-step plan to hit your target.
Read guideHow Much Should I Save by Age 40?
How much should you have saved by age 40? Net worth benchmarks, retirement targets, and how to accelerate if you're behind.
Read guideHow Much Will $2,000 a Month Grow To?
See exactly how $2,000 invested monthly grows over 10, 20, and 30 years at different return rates — with realistic examples and a free calculator.
Read guideHow Much Will $300 a Month Grow To?
See how $300 a month invested grows over 10, 20, and 30 years at 4%, 7%, and 10% returns — with worked examples and a free calculator.
Read guideHow Much Will $5,000 Invested Grow To?
See what a one-time $5,000 investment becomes after 10, 20, 30, and 40 years at different return rates — with worked examples and a free calculator.
Read guideHow to Build Wealth in Your 20s
A practical roadmap to build serious wealth in your 20s — save more, invest early, avoid lifestyle creep, and let compounding do the heavy lifting.
Read guideHow to Build Wealth in Your 30s
A practical wealth-building plan for your 30s — peak earning years, family costs, and the catch-up moves that put you on track for retirement.
Read guideHow to Plan a Savings Goal
Turn any savings target into a realistic monthly plan in 5 steps.
Read guideHow to Save $10,000 Fast
An aggressive 6–12 month playbook for hitting $10K quickly.
Read guideHow to Save Money Faster
Practical, repeatable tactics for boosting your monthly savings rate.
Read guideSavings by Age: Are You On Track?
Benchmark how much you should have saved by age 30, 40, 50, and 60 — with practical guidance if you're behind.
Read guideThe 4% Rule Explained
The 4% rule says you can safely withdraw 4% of your portfolio each year in retirement. Here's the math, history, and modern critiques.
Read guideFrequently asked questions
Where should a beginner start with investing?
Open a tax-advantaged account (401(k) up to the employer match, then a Roth IRA), buy a low-cost diversified index fund, automate monthly contributions, and ignore the daily news. That single workflow beats 90% of active investors over decades.
How much should I invest each month?
A common target is 15% of gross income for retirement. If that's not realistic, start with whatever you can sustain — even $50 or $100 — and increase it $10–$25 every six months or with each raise.
What return rate is realistic?
Long-term, a diversified stock portfolio has averaged about 7% per year after inflation (10% before). Use 6–7% for conservative planning. Don't assume more than 10%.
Should I invest or pay down debt first?
Pay off anything above ~7% (most credit cards) before investing beyond an employer match. Below 5%, it's usually fine to split between the two.
Is it too late to start investing?
No. The best time to start was 20 years ago — the second best is today. Starting at 40 or 50 still produces meaningful results, especially if you raise your contribution rate.