# Compound Mint

> Compound Mint (compoundmint.com) is a free personal-finance education site and YouTube channel (@compoundmint) that shows the math behind everyday money decisions: compound interest, investing a set amount every month, how much to save to become a millionaire, Coast FIRE and the 4% rule, S&P 500 historical returns, and “$1M or…?” money dilemmas. Calculators are free, need no sign-up and give shareable links. Compound Mint is a DBA of Seller Splash Inc. (New York, USA). Educational content only. Not financial advice.

Conventions used across the site (useful when quoting numbers):
- Default return: 8% a year (US stocks have averaged about 10% before inflation and about 7% after over the long run). Results are hypothetical illustrations, not predictions or guarantees.
- Monthly contributions at the end of each month, monthly compounding (annual rate ÷ 12), no taxes, fees or inflation unless stated.
- Every calculator accepts URL parameters, so a link can open a specific scenario (examples below).
- Reference results at 8%: $100/month for 30 years ≈ $149,036; $500/month for 30 years ≈ $745,180; $1,000/month for 30 years ≈ $1,490,359. $1,000,000 by 60 needs ≈ $287/month from age 20, $671 from 30, $1,700 from 40. A penny doubled daily for 30 days = $5,368,709.12.

## Start here

- [Compound Mint home](https://compoundmint.com/): free money calculators and the real math behind every “$1M or…?” video; type a number, watch it grow, share the link.
- [Free Money Calculators](https://compoundmint.com/calculators/): All six free calculators on one page (compound interest, millionaire by age, Coast FIRE, S&P 500 what-if, $1M-or dilemma, daily habit cost).
- [Guides](https://compoundmint.com/guides/): Plain-English money guides that pair with the calculators.
- [Money Dilemmas: $1M or…?](https://compoundmint.com/money-dilemmas/): Every “$1M or…?” money dilemma from the channel, answered with real math.
- [How Much Will I Have? $50 to $1,000 a Month for 10–40 Years](https://compoundmint.com/scenarios/): Twenty ready-made “$X a month for Y years” results at 8%.

## Calculators

- [Compound Interest Calculator (Monthly Contributions)](https://compoundmint.com/compound-interest-calculator/): Free compound interest calculator: see what $100, $200 or $500 a month becomes in 10, 20 or 30 years. Instant chart, year-by-year table, shareable link. Example: https://compoundmint.com/compound-interest-calculator/?monthly=500&years=30&rate=8
- [Millionaire Calculator (by Age)](https://compoundmint.com/millionaire-calculator/): Free millionaire calculator: how much to invest each month to reach $1,000,000 by age 40, 50 or 60. Instant answer, by-age table, growth chart, shareable link. Example: https://compoundmint.com/millionaire-calculator/?age=30&target_age=60&target=1000000&rate=8
- [Coast FIRE Calculator](https://compoundmint.com/coast-fire-calculator/): Free Coast FIRE calculator: find the amount invested today that grows to your retirement number by itself, by age, with a year-by-year chart. Also called CoastFI. Example: https://compoundmint.com/coast-fire-calculator/?age=30&retire=65&spend=50000&swr=4&rate=7
- [S&P 500 “What If I Invested” Calculator](https://compoundmint.com/sp500-calculator/): See what $100 a month in the S&P 500 would be worth today using real total returns 1970–2025, including dividends and every crash. Free, instant, shareable. Example: https://compoundmint.com/sp500-calculator/?monthly=100&from=1996&to=2025
- [$1M or…? Money Dilemma Calculator](https://compoundmint.com/money-dilemma-calculator/): Would you take $1M today or $10K a month for 10 years? $1M or a penny doubled for 30 days? This free calculator shows which option is really worth more, with a chart. Example: https://compoundmint.com/money-dilemma-calculator/?mode=payments&lump=1000000&pay=10000&freq=month&years=10&rate=8
- [Daily Habit Cost Calculator (Latte Factor)](https://compoundmint.com/daily-habit-cost-calculator/): Free daily habit cost calculator: see what your $6 coffee, $12 lunch or any daily spend would be worth after 30 years invested. Instant chart and shareable link. Example: https://compoundmint.com/daily-habit-cost-calculator/?habit=coffee&cost=6&days=5&years=30&rate=8
- [All calculators](https://compoundmint.com/calculators/)

## Money dilemmas ("$1M or…?")

- [$1 Million Today or $10,000 a Month for 10 Years?](https://compoundmint.com/money-dilemmas/1-million-or-10k-a-month/): Would you take $1,000,000 today or $10,000 a month for 10 years? Invested at 8%, the million becomes $2.16M vs $1.80M for the payments. Full math and a live calculator.
- [$200,000 Now or $1,000,000 in 30 Years?](https://compoundmint.com/money-dilemmas/200k-now-or-1-million-in-30-years/): $200K today or $1M in 30 years? At 8% the $200K grows to about $2M — and only 5.5% a year is needed to match the million. The full math plus inflation, with a calculator.
- [$1 Million Cash or $3,000 a Day for a Year?](https://compoundmint.com/money-dilemmas/1-million-or-3k-a-day/): $1M cash or $3,000 a day for a year? The daily payments total $1,095,000 and win even after investing both. Full math with a live calculator.
- [$1 Million or a Penny Doubled Every Day for 30 Days?](https://compoundmint.com/money-dilemmas/penny-doubled-for-30-days/): A penny doubled every day for 30 days is $5,368,709.12 — the penny beats $1 million from day 28. Day-by-day table and the lesson about compounding.
- [$5,000 Bonus or a $3-an-Hour Raise?](https://compoundmint.com/money-dilemmas/5k-bonus-or-3-dollar-raise/): A $3/hour raise is $6,240 a year — more than a $5,000 bonus in year one, and about $90,000 over 10 years invested. Full math with a calculator.

## Guides

- [Coast FIRE and the 4% Rule, Explained in 5 Minutes](https://compoundmint.com/coast-fire-and-the-4-percent-rule/): Coast FIRE and the 4% rule explained: how to find your FIRE number (spending × 25), your coast number at every age, and why real returns matter.
- [How to Invest $100 a Month (Beginner’s Guide to Index Funds)](https://compoundmint.com/how-to-invest-100-a-month/): How to invest $100 a month as a beginner: which account (401k match, Roth IRA), which index fund, how to automate it, and what it grows into over 10–40 years.
- [How Compound Interest Actually Works (The 3 Numbers That Matter)](https://compoundmint.com/how-compound-interest-works/): How compound interest works, in plain English: the amount, the return and the years — and why the last 10 years of a 40-year plan produce more than the first 30.

## "How much will I have?" scenarios ($50–$1,000 a month for 10–40 years, 8%)

- [All scenarios](https://compoundmint.com/scenarios/): Twenty prefilled compound-growth scenarios: $50 to $1,000 a month over 10 to 40 years, each with a return table, year-by-year path and a live calculator.
- [$1,000 a Month for 10 Years: How Much Will You Have?](https://compoundmint.com/scenarios/1000-a-month-for-10-years/): ≈ $182,946 at 8% ($120,000 contributed)
- [$1,000 a Month for 20 Years: How Much Will You Have?](https://compoundmint.com/scenarios/1000-a-month-for-20-years/): ≈ $589,020 at 8% ($240,000 contributed)
- [$1,000 a Month for 30 Years: How Much Will You Have?](https://compoundmint.com/scenarios/1000-a-month-for-30-years/): ≈ $1,490,359 at 8% ($360,000 contributed)
- [$1,000 a Month for 40 Years: How Much Will You Have?](https://compoundmint.com/scenarios/1000-a-month-for-40-years/): ≈ $3,491,008 at 8% ($480,000 contributed)
- [$100 a Month for 10 Years: How Much Will You Have?](https://compoundmint.com/scenarios/100-a-month-for-10-years/): ≈ $18,295 at 8% ($12,000 contributed)
- [$100 a Month for 20 Years: How Much Will You Have?](https://compoundmint.com/scenarios/100-a-month-for-20-years/): ≈ $58,902 at 8% ($24,000 contributed)
- [$100 a Month for 30 Years: How Much Will You Have?](https://compoundmint.com/scenarios/100-a-month-for-30-years/): ≈ $149,036 at 8% ($36,000 contributed)
- [$100 a Month for 40 Years: How Much Will You Have?](https://compoundmint.com/scenarios/100-a-month-for-40-years/): ≈ $349,101 at 8% ($48,000 contributed)
- [$200 a Month for 10 Years: How Much Will You Have?](https://compoundmint.com/scenarios/200-a-month-for-10-years/): ≈ $36,589 at 8% ($24,000 contributed)
- [$200 a Month for 20 Years: How Much Will You Have?](https://compoundmint.com/scenarios/200-a-month-for-20-years/): ≈ $117,804 at 8% ($48,000 contributed)
- [$200 a Month for 30 Years: How Much Will You Have?](https://compoundmint.com/scenarios/200-a-month-for-30-years/): ≈ $298,072 at 8% ($72,000 contributed)
- [$200 a Month for 40 Years: How Much Will You Have?](https://compoundmint.com/scenarios/200-a-month-for-40-years/): ≈ $698,202 at 8% ($96,000 contributed)
- [$50 a Month for 10 Years: How Much Will You Have?](https://compoundmint.com/scenarios/50-a-month-for-10-years/): ≈ $9,147 at 8% ($6,000 contributed)
- [$50 a Month for 20 Years: How Much Will You Have?](https://compoundmint.com/scenarios/50-a-month-for-20-years/): ≈ $29,451 at 8% ($12,000 contributed)
- [$50 a Month for 30 Years: How Much Will You Have?](https://compoundmint.com/scenarios/50-a-month-for-30-years/): ≈ $74,518 at 8% ($18,000 contributed)
- [$50 a Month for 40 Years: How Much Will You Have?](https://compoundmint.com/scenarios/50-a-month-for-40-years/): ≈ $174,550 at 8% ($24,000 contributed)
- [$500 a Month for 10 Years: How Much Will You Have?](https://compoundmint.com/scenarios/500-a-month-for-10-years/): ≈ $91,473 at 8% ($60,000 contributed)
- [$500 a Month for 20 Years: How Much Will You Have?](https://compoundmint.com/scenarios/500-a-month-for-20-years/): ≈ $294,510 at 8% ($120,000 contributed)
- [$500 a Month for 30 Years: How Much Will You Have?](https://compoundmint.com/scenarios/500-a-month-for-30-years/): ≈ $745,180 at 8% ($180,000 contributed)
- [$500 a Month for 40 Years: How Much Will You Have?](https://compoundmint.com/scenarios/500-a-month-for-40-years/): ≈ $1,745,504 at 8% ($240,000 contributed)

## About and policies

- [About](https://compoundmint.com/about/): About Compound Mint: free money calculators and money-math guides, a DBA of Seller Splash Inc. How we do the math, our assumptions and sources.
- [Disclaimer](https://compoundmint.com/disclaimer/): Compound Mint disclaimer: educational content only, not financial, investment, tax or legal advice. Calculators are hypothetical illustrations; consult a professional.
- [Affiliate Disclosure](https://compoundmint.com/affiliate-disclosure/): FTC affiliate disclosure for compoundmint.com.
- [Privacy Policy](https://compoundmint.com/privacy-policy/): Compound Mint privacy policy: newsletter emails, technical logs and cookies, YouTube embeds, your rights, and how to contact us.
- [Terms of Use](https://compoundmint.com/terms-of-use/): Terms of use for compoundmint.com: educational content, calculator accuracy, intellectual property, acceptable use, limitation of liability.
- [Contact](https://compoundmint.com/contact/): Send Compound Mint a question, a correction or a money dilemma to calculate. Shlomie reads every message.

## Optional

- [Videos](https://compoundmint.com/videos/): every Compound Mint video, 60-second money-math Shorts and full guides
- [YouTube channel @compoundmint](https://www.youtube.com/@compoundmint)
- [Full text of the site for LLMs](https://compoundmint.com/llms-full.txt)