pennycalc.com

Financial math
you can verify.

27 calculators and reference pages that show every step. Every assumption stated, every default overridable. All math runs client-side - your data never leaves your browser.

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Paycheck Calculator

LIVE
$75,000
$25K $300K
Take-home
$55,088
Federal
$8,236
FICA
$5,738
State
$3,750
Effective Rate
23.6%
Monthly Take-home
$4,591
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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.

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

Every calculator shows amortization schedules, bracket breakdowns, and year-by-year projections. Not just the answer - the proof.

defaults: overridable

Your Assumptions

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

dataCollection: none

Privacy First

All math runs in your browser. No accounts, no email capture, no server calls. Your financial data never leaves your device.

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

 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 100% free - no signup, no email capture, no paywall. All calculations run in your browser; we never collect your financial data.
How accurate are the calculations?
Mortgage payments match a lender's Loan Estimate to the dollar (same amortization formula, same PMI thresholds at 80% and 78% LTV). Paycheck withholding matches IRS Publication 15-T tables and state Department of Revenue schedules. Tax bracket math uses the IRS Rev. Proc. inflation-adjusted brackets for the relevant year. If our number does not match your lender's, your paycheck's, or your statement's, treat it as a bug, not a simplification, and email [email protected].
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?
No. All calculations run entirely in your browser via JavaScript. Your data never leaves your device, never hits our servers. No accounts, no logins, no personal information required.
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 was started by a private-equity analyst tired of black-box financial calculators. Josh owns the mortgage, tax, retirement, and capital-gains tools. Jessie writes the paycheck, 401(k), and Roth coverage. Michael handles the debt, auto-loan, and implementation side. Every tool models the math the same way they model it at work - transparently.

About the team