"I sit down on the last Sunday of every month and plan my zero-based budget here. My salary, my debt, my savings goals — none of it leaves my laptop. That's exactly how financial planning should work."

Marcus D.

High School Teacher

"The ADP paycheck calculator showed me exactly what my take-home would be if I switched from salary to hourly. I ran six different scenarios before my HR meeting. No account needed, nothing saved — just clarity when I needed it."

Christine W.

Marketing Manager

"The debt snowball calculator finally made my student loans feel beatable. Seeing the payoff timeline shrink as I added extra payments was the motivation I needed. And I didn't have to hand my financial details to another app that would try to sell me something."

DeShawn J.

Recent Graduate, $47K in Loans

The Simple Toolbox's free finance calculators cover compound interest, debt payoff, retirement planning, and investment analysis. Every tool runs in your browser — no account, no data uploaded, no subscription.

Frequently Asked Questions

What finance calculators are available?

Compound interest, debt snowball, CD vs HYSA comparison, ROI calculator, rule of 72, rate calculator, and percentage calculator — all free, all browser-based.

Are these calculators accurate?

All use standard financial formulas validated against published sources. Results are estimates for planning purposes — consult a financial advisor for personalized advice.

Do I need to create an account?

No. Every calculator works instantly with no sign-up, no email, and no subscription required.

Is my financial data private?

Yes. Every calculation runs locally in your browser. No numbers you enter are ever sent to a server or stored anywhere.