pennycalc.com

Financial math
you can verify.

27 calculators and reference pages that show every step. Every assumption stated, every default overridable. Current calculator inputs stay client-side and are excluded from analytics. Privacy details.

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Paycheck Calculator

LIVE
$75,000
$25K $300K

Illustrative estimate for a single filer using a flat 5% state income tax and no pre-tax deductions.

Take-home
$57,843
Federal
$7,670
FICA
$5,738
State
$3,750
Effective Rate
22.9%
Monthly Take-home
$4,820
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Every calculator, one place

Click a category to filter, or browse them all. Each tool shows the math behind the number.

Reference datasets

The data behind the calculators

Primary-source series, charted at build time. Every chart is downloadable in light and dark.

Bar chart of S&P 500 annual returns, 1928-2025

S&P 500 Return History

Every annual total return since 1928. $1,000 invested in 1980 became $192,219 by end-2025.

 Bar chart of U.S. annual inflation, 1913-2026

Inflation Time Machine

What any dollar amount from any year buys today - and how fast each era halved the value of cash.

 Line chart of the monthly cost of the median U.S. house, 1963-2026

Median Home Price History

The 1981 median house cost $2,802/month in 2026 dollars - more than the recent median-home estimate using Freddie Mac's July 16, 2026 6.55% average.

 Line chart of the top marginal federal income tax rate, 1913-2026

Tax Bracket History

The top marginal rate, 1913-2026: from 7% to 94% in 1944 to 37% today, with every major tax act.

Why PennyCalc

Built by a PE professional who models leveraged buyouts for a living. These are the tools we wish existed.

showWork: true

Visible Math

Core calculators expose the relevant schedules, bracket breakdowns, or year-by-year projections, with assumptions and limitations beside the result.

defaults: overridable

Your Assumptions

PMI rates, tax filing status, employer match - every default can be changed. Plug in your real numbers for real answers.

inputValuesToAnalytics: none

Privacy First

Current inputs and results stay in your browser and are excluded from analytics. No accounts or email capture. Read the legacy-link caveat.

Guides & References

Deep dives, worked examples, and reference tables.

Reference

Financial Glossary

50+ terms in plain English

 Tax

2026 Tax Brackets

Rates, deductions, worked examples

 Tax

Tax Brackets Hub

Current year + 1913-2026 history chart

 Retirement

2026 401(k) Limits

Deferrals, catch-up, mega backdoor

 Retirement

Roth vs. Traditional IRA

Side-by-side tax math

 Debt

Avalanche vs. Snowball

Worked example with $47K debt

 Investing

Compound Interest

Rule of 72 + growth tables

 Investing

S&P 500 Time Machine

$1,000 in any year since 1928

 Investing

Inflation Time Machine

Any dollar amount, any year since 1913

 Mortgage

Home Price History

The median house, 1963-2026, in real dollars

 Income

Hourly to Salary

$20/hr = $41,600 - and what you keep

 Income

Salary After Taxes

$50K-$200K take-home breakdowns

 Tax

Self-Employment Tax

15.3% SE tax, quarterly payments

Frequently Asked Questions

Are PennyCalc's calculators really free?
Every calculator is free to use - no signup, email capture, or paywall. Current calculator inputs are processed in your browser and are not sent to analytics. See the privacy policy for the limited caveat that applies when opening an older query-string scenario link.
How accurate are the calculations?
We implement cited formulas and test worked examples, including IRS tax brackets, federal withholding tables, amortization, and state rules in scope. Results are estimates: a lender, employer, servicer, or tax return can differ because of timing, elections, local rules, fees, rounding, or inputs our tools do not model. Review the stated assumptions and report a suspected error through our corrections page.
What makes PennyCalc different?
Visible math (every step, not just the answer). Overridable assumptions (change any default). Complex scenarios other calculators skip - PMI cancellation at 78% LTV, AMT exemption phaseouts, bracket stacking.
Do you store my financial information?
Current calculator changes stay in your browser, and analytics events exclude input values and calculated results. We do not offer accounts or store calculator scenarios on our servers. Older query-string scenario links can expose their URL values to our edge on the initial request; the privacy policy explains how those links are normalized.
Can I use PennyCalc for tax planning?
Our tax calculators are excellent for estimating liability and exploring scenarios. For filing taxes or major financial decisions, consult a qualified CPA or tax advisor.

Built by people who use these tools

PennyCalc is built and reviewed by three people with backgrounds in finance, consulting, and technology. Josh, formerly at Houlihan Lokey, owns the mortgage, tax, retirement, and capital-gains tools. Jessie, formerly at McKinsey & Company, writes the paycheck, 401(k), and Roth coverage. Michael, formerly at Deloitte, handles the debt, auto-loan, and implementation side. Every tool is designed to show its inputs, assumptions, and math.

About the team