SimpleToolbox

Free Online Web Tools for
Developers

The ultimate collection of free online calculators, formatters, and generators. Process PDFs, format code, and optimize media instantly and securely in your browser.

Our Most Popular Tools

Hand-picked tools loved by thousands of professionals worldwide.

PERSONAL FINANCE

Budget Planner

Plan your monthly budget and track expenses.

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PERSONAL FINANCE

ADP Paycheck Calculator

Estimate net take-home pay from hourly or salary wages.

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TRADING

Prop Firm Breakeven

Calculate exactly what you need to pass your evaluation.

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E-COMMERCE

Dropshipping Margin

Calculate true profit margins including ad spend and fees.

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SOCIAL

Sponsorship Calc

Calculate fair brand deal rates for YouTube integrations.

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SEO

Keyword ROI

Calculate the actual monetary value of a ranking keyword.

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DEVELOPER

JSON Formatter

Validate and beautify JSON payloads.

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MEDIA

PDF Merger

Merge multiple PDFs locally without uploading.

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Privacy Tools

Stay secure
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Password Security

The Platform Advantage

Built differently from the ground up.

100% Client-Side Processing

Your sensitive data never leaves your device. We convert PDFs, format JSON, and check visas entirely within your browser for absolute privacy.

Zero Friction Design

No 'Sign up to export' popups. No hidden paywalls. Just instantly loading, beautifully designed utilities ready when you need them.

Built for Professionals

From Prop Firm profit calculators to complex JSON validators, our tools are engineered for accuracy and speed for the modern worker.

Trusted by real professionals.

Don't just take our word for it. See how The Simple Toolbox is helping people work faster every day.

"The N-400 calculator saved me literally hours of checking passport stamps against spreadsheets. The fact that it processes in the browser means I didn't have to worry about putting my dates into a random server."

A
Aleksandra M.
Recent Citizen

"I use the JSON formatter and Regex tester daily. The lack of ads breaking the layout and the dark mode makes it my go-to developer utility bookmarked on every machine."

D
David Chen
Senior Frontend Engineer

"The Prop firm contract sizing calculator is perfectly built. Finding one that actually accounts for trailing drawdown properly is rare. Simple, fast, and does exactly what it says."

M
Marcus L.
Funded Trader

Frequently Asked Questions

Everything you need to know about the platform and how we manage your data.

No. The Simple Toolbox is 100% free and requires zero registration. We believe utility tools should be instantly accessible without friction.