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Financial Education Tools — Free Calculators That Show Their Work

This page is for learners, students, and curious adults who want to understand the mechanics behind compound growth, inflation, taxes, and investing. These calculators are designed to teach, not just output a number, so you can see the equations and follow the logic yourself.

18 live calculatorsTransparent formulas

🧾Tax Calculators50 📊Business Calculators59 ❤️Health & Lifestyle Calculators4 🏠Real Estate Calculators8 ✨Lifestyle Calculators4

Compound Interest Calculator

See how your money grows with compound interest and regular contributions. Watch year-by-year growth, apply the Rule of 72, and see the real power of compounding.

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Formula

A = P(1 + r/n)^(nt)

Time Value of Money Calculator

Solve any TVM variable: present value, future value, payment, interest rate, or number of periods. Supports ordinary annuity and annuity-due with amortization schedule and sensitivity analysis.

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GPA Calculator

Calculate your cumulative GPA on the 4.0 scale from letter grades and credit hours

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Inflation Calculator

Find out what any dollar amount is worth across time — past or future. Powered by CPI data from 1913–2024 with actual historical rates. See how inflation erodes purchasing power and what you need to earn to keep up.

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Formula

adjusted = amount × ∏(1 + CPIᵧ/100)

Compound Interest Visualizer

Student tool for ages 13-21. Interactive sliders for starting amount, monthly contribution, annual interest rate (1-15%), and years (1-40). SVG line chart shows compound growth vs saving-only side by side. Rule of 72 doubling time. Preset scenarios (first job paycheck, $25/week from age 16, birthday money). ShowMath walks through every formula including A = P(1 + r/n)^(nt). Outputs: final balance, total contributed, total interest earned (the wow number), interest multiplier.

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Formula

A = P(1 + r/n)^(nt) + PMT × ((1 + r/n)^(nt) − 1) / (r/n)

What Will My First Paycheck Actually Be?

Student tool for ages 16-21. Enter hourly wage and hours per week to see exactly where every dollar goes. Shows gross pay → federal income tax (2024 standard withholding) → Social Security (6.2%) → Medicare (1.45%) → state income tax → net take-home. Friendly explanations for each deduction. W-2 vs 1099 contractor comparison showing why contractors pay more. ShowMath walks through every step.

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Formula

netPay = gross − federalTax − SS(6.2%) − Medicare(1.45%) − stateTax

How Credit Scores Actually Work

See exactly how FICO scores are calculated — payment history, utilization, account age, and more. Simulate your score and explore what-if scenarios.

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Formula

Score = Σ(factor × weight) + 300

What Does Your Hourly Wage Actually Buy?

Translate your hourly rate into real take-home pay after taxes. See what your paycheck actually covers — and what things really cost in hours of work.

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Formula

Net = Gross − FICA − Federal Tax − State Tax

What Will Your Student Loan Really Cost You?

See the true cost of your student loan — total interest, monthly payment, and exactly how much you'll pay back vs. what you borrowed.

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Formula

Payment = P×r×(1+r)^n / ((1+r)^n − 1)

What Inflation Is Doing to Your Money

See how inflation erodes purchasing power over time. Enter your salary or savings to see what it buys in today's dollars vs 5, 10, 20, or 30 years from now. Compare inflation vs HYSA (4.5%) vs S&P 500 (10%). Historical presets for 1970s, 2022 peak, and current 2024 CPI.

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Financial Independence: How Close Are You?

Calculate your FI number (expenses × 25), years to financial independence, and see exactly how dramatically your savings rate shortens the timeline.

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Formula

FI Number = Annual Expenses × 25

Is College Worth It? ROI Calculator

Honest, data-driven college ROI calculator. Enter total cost, loan amount, expected salaries, and years to graduate to see lifetime earnings premium, break-even years, 40-year NPV, and side-by-side comparison with trade school. No spin — just the math.

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Stock Market Basics: What Is a Share Actually Worth?

Understand P/E ratios, earnings yield, market cap, and dollar-cost averaging with interactive simulators. See why index funds beat most active managers.

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Formula

P/E = Share Price ÷ Earnings Per Share

How Interest Rates Affect Everything

See how Fed rate changes ripple through your mortgage, car loan, savings account, and credit card. Enter your actual balances and simulate a rate cut or hike to see your net monthly impact.

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Formula

net impact = ARM savings + card savings − savings yield loss

Opportunity Cost Calculator

See the true cost of everyday spending habits. That daily $5 coffee is $170,000 in 30 years if invested at 7%. Calculate what any habit costs in foregone investment returns — with year-by-year growth table.

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Formula

FV = annual cost × [(1+r)^n − 1] / r

GDP & Inflation: What the Economy Means for Your Wallet

Connect macro economics to your finances. Learn real vs nominal GDP, track CPI inflation 2015–2024, calculate your personal inflation rate based on your spending mix, and find your real return with the Fisher equation.

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Formula

real return = (1+nominal)/(1+inflation) − 1

529 College Savings Calculator

Is your 529 on track? Project your balance at age 18, see the inflation-adjusted 4-year cost, close your funding gap, and estimate state tax deduction savings.

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Formula

FV = PV×(1+r)^n + PMT×[(1+r)^n−1]/r

Time Value of Money Calculator

Future value, present value, required return, and required time — with annuity mode, inflation adjustment via Fisher equation, and year-by-year compound schedule.

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Formula

FV = PV x (1+r)^n