# InterestCal

> InterestCal is a free financial calculator platform offering 30+ interactive calculators covering compound interest, retirement planning, debt payoff, salary and tax, investment growth, and currency conversion. All tools are free, no sign-up required, and backed by editorial content written by personal finance writer Daniel Lance.

## Core Site

- [Home](https://interestcal.com/): Free financial calculators and personal finance tools
- [All Calculators](https://interestcal.com/calculators/): Browse all 30+ calculators by category
- [Guides](https://interestcal.com/guides/): In-depth personal finance guides
- [Blog](https://interestcal.com/blog/): Articles on investing, debt, retirement, and planning
- [Glossary](https://interestcal.com/definitions/): Financial term definitions
- [Currency Converter](https://interestcal.com/converter/currency-converter): Live exchange rates for 30+ currencies
- [Embed Calculators](https://interestcal.com/embed/): Free embeddable calculators for websites and blogs
- [Author: Daniel Lance](https://interestcal.com/authors/daniel-lance): Personal Finance Writer & Calculator Enthusiast

## Investment Calculators

- [Compound Interest Calculator](https://interestcal.com/calculators/compound-interest): Calculate how money grows with compound interest over time; supports monthly contributions and variable compounding periods
- [Investment Growth Calculator](https://interestcal.com/calculators/investment-growth): Project portfolio value with initial investment plus regular contributions
- [ROI Calculator](https://interestcal.com/calculators/roi): Calculate Return on Investment as a percentage
- [ROI + CAGR Calculator](https://interestcal.com/calculators/roi-cagr): Combined ROI and Compound Annual Growth Rate calculator
- [SIP Calculator](https://interestcal.com/calculators/sip): Calculate returns on Systematic Investment Plans (monthly recurring investments)
- [SIP + Lump Sum Calculator](https://interestcal.com/calculators/sip-lumpsum): Combine one-time and recurring investments
- [Dividend Reinvestment Calculator](https://interestcal.com/calculators/dividend-reinvestment): Model DRIP (dividend reinvestment plan) compounding over time
- [Dividend Yield on Cost](https://interestcal.com/calculators/dividend-yield-on-cost): Calculate personal dividend yield based on original purchase price

## Retirement Calculators

- [FIRE Number Calculator](https://interestcal.com/calculators/fire-number): Calculate the portfolio size needed for Financial Independence / Retire Early
- [Early Retirement Calculator](https://interestcal.com/calculators/early-retirement): Find out what age you can retire based on savings rate and expenses
- [401(k) Calculator](https://interestcal.com/calculators/401k): Project 401(k) balance at retirement with employer match
- [SWR Drawdown Calculator](https://interestcal.com/calculators/swr-drawdown): Safe Withdrawal Rate simulation for retirement portfolios
- [Sequence of Returns Risk Calculator](https://interestcal.com/calculators/sequence-of-returns): Model how early portfolio losses affect retirement sustainability

## Debt Calculators

- [Mortgage Payoff Calculator](https://interestcal.com/calculators/mortgage-payoff): Calculate time and interest saved with extra mortgage payments
- [Student Loan Calculator](https://interestcal.com/calculators/student-loan): Estimate student loan monthly payments and payoff timeline
- [Car Loan Calculator](https://interestcal.com/calculators/car-loan): Calculate monthly car payment and total financing cost
- [Loan Amortization Calculator](https://interestcal.com/calculators/loan-amortization): Full amortization schedule with principal/interest breakdown
- [Credit Card Payoff Calculator](https://interestcal.com/calculators/credit-card-payoff): Find how long to pay off credit card debt and total interest paid
- [Debt-to-Income Ratio Calculator](https://interestcal.com/calculators/debt-to-income): Calculate DTI ratio for loan eligibility assessment

## Planning Calculators

- [Salary Calculator](https://interestcal.com/calculators/salary): Take-home pay after federal income tax, Social Security, Medicare, and pre-tax deductions; uses 2026 US tax brackets
- [Inflation Impact Calculator](https://interestcal.com/calculators/inflation-impact): Show how inflation erodes purchasing power over time
- [Savings Goal Calculator](https://interestcal.com/calculators/savings-goal): Calculate monthly savings needed to reach a target amount
- [Emergency Fund Calculator](https://interestcal.com/calculators/emergency-fund): Determine how much to keep in an emergency fund (3–6 months expenses)
- [Net Worth Calculator](https://interestcal.com/calculators/net-worth): Track total assets minus liabilities
- [Rule of 72 Calculator](https://interestcal.com/calculators/rule-of-72): Estimate how long it takes money to double at a given interest rate

## Stocks & Crypto Calculators

- [Crypto Profit Calculator](https://interestcal.com/calculators/crypto-profit): Calculate cryptocurrency trading profit or loss after fees
- [Stock Average Cost Calculator](https://interestcal.com/calculators/stock-average-cost): Compute average cost basis across multiple stock purchases
- [Capital Gains Tax Calculator](https://interestcal.com/calculators/capital-gains): Estimate US capital gains tax on investment sales
- [Position Size Calculator](https://interestcal.com/calculators/position-size): Determine trades size based on account risk tolerance
- [Stock Return Calculator](https://interestcal.com/calculators/stock-return): Calculate total stock return including dividends and price appreciation

## Currency Converter

- [Currency Converter](https://interestcal.com/converter/currency-converter): Live mid-market exchange rates for USD, EUR, GBP, INR, JPY, AUD, CAD and 25+ more currencies; updated daily via open.er-api.com

## Key Blog Articles

- [How to Calculate Return on Investment (ROI)](https://interestcal.com/blog/how-to-calculate-return-on-investment.html): Formulas, worked examples, and ROI vs CAGR comparison
- [What Is Compound Interest and How Does It Work?](https://interestcal.com/blog/what-is-compound-interest-and-how-does-it-work.html): Compound interest explained with the A = P(1 + r/n)^nt formula
- [What Is CAGR and How to Calculate It?](https://interestcal.com/blog/what-is-cagr-and-how-to-calculate-it.html): Compound Annual Growth Rate formula and examples
- [Debt Avalanche vs Snowball: Which Method Is Best?](https://interestcal.com/blog/debt-avalanche-vs-snowball-which-method-is-best.html): Interest-first vs smallest-balance-first debt payoff strategies
- [What Is a Good Debt-to-Income Ratio?](https://interestcal.com/blog/what-is-a-good-debt-to-income-ratio.html): DTI thresholds for mortgages and lending
- [Roth IRA vs Traditional IRA: Which Is Better?](https://interestcal.com/blog/roth-ira-vs-traditional-ira-which-is-better.html): Tax-now vs tax-later retirement account comparison
- [FIRE Number Planning With Realistic Assumptions](https://interestcal.com/blog/fire-number-planning-with-realistic-assumptions.html): 4% rule, safe withdrawal, and portfolio sizing for early retirement
- [How Inflation Affects Your Savings and What to Do](https://interestcal.com/blog/how-inflation-affects-your-savings-and-what-to-do.html): Real vs nominal returns and inflation-hedging strategies
- [Zero-Based Budgeting: The Complete Guide](https://interestcal.com/blog/zero-based-budgeting-guide.html): How to assign every dollar a job each month
- [Building Wealth in Your 20s](https://interestcal.com/blog/building-wealth-in-your-20s.html): Index funds, 401(k), emergency fund, and compound growth starting early
- [The 4% Rule Explained](https://interestcal.com/blog/the-4-percent-rule-explained-retirement-withdrawal-strategy-and-fire-calculator.html): Retirement withdrawal strategy and FIRE calculator guide
- [How to Start Investing With Little Money](https://interestcal.com/blog/how-to-start-investing-with-little-money.html): Index funds, fractional shares, and dollar-cost averaging for beginners

## Key Guides

- [Compound Interest Explained](https://interestcal.com/guides/compound-interest-explained.html): Full conceptual guide to compound interest with formula derivations
- [How to Calculate Compound Interest](https://interestcal.com/guides/how-to-calculate-compound-interest.html): Step-by-step compound interest calculations
- [How to Start Investing](https://interestcal.com/guides/how-to-start-investing.html): Beginner's complete investing guide
- [FIRE Guide](https://interestcal.com/guides/fire-guide.html): Financial Independence Retire Early complete guide
- [Retirement Planning 101](https://interestcal.com/guides/retirement-planning-101.html): Foundational retirement planning concepts
- [Debt Snowball vs Avalanche](https://interestcal.com/guides/debt-snowball-vs-avalanche.html): Comparative guide to debt repayment strategies
- [Understanding Amortization](https://interestcal.com/guides/understanding-amortization.html): How loan amortization schedules work
- [Tax-Efficient Investing](https://interestcal.com/guides/tax-efficient-investing.html): Strategies to keep more of your investment returns
- [Dividend Investing Guide](https://interestcal.com/guides/dividend-investing-guide.html): Building a dividend income portfolio
- [Asset Allocation Guide](https://interestcal.com/guides/asset-allocation-guide.html): How to balance stocks, bonds, and cash by age and risk tolerance