ToolSelf Blog
Guides on taxes, finance, business, and practical tools for freelancers and everyone.
Building Multiple Income Streams: Beyond Hourly Work
Relying on hourly income is risky. Explore passive income options: digital products, affiliates, retainers, and more.
Wedding Budget Calculator: What 30K Actually Covers
Average US wedding cost is $33,000. Here is how that breaks down by category — and where most couples overspend.
Profit Margin vs Markup: What's the Difference?
Profit margin and markup are NOT the same thing. Here's the difference and why it matters for your pricing.
Percentage Calculations: 7 Common Mistakes and How to Avoid Them
Percentages look easy but the language traps even smart people. Here are the mistakes that show up in everyday math.
Closing Costs Explained: The 3-5% Most Buyers Forget
Beyond the down payment, expect another 3-5% of the home price in closing costs. Here is the full itemized breakdown.
PNG vs JPG vs WebP: Choosing the Right Image Format
PNG for graphics with sharp edges. JPG for photographs. WebP for everything new. Picking wrong inflates page weight.
MP3 vs AAC vs FLAC: Audio Format Comparison
MP3 is the universal lossy default. AAC is more efficient at the same bitrate. FLAC is lossless. Each has its use.
Payroll Taxes Explained: FICA, Medicare, Social Security
If you have employees, you're responsible for payroll taxes. Here's what FICA, Medicare, and Social Security mean for your business.
Estimated Quarterly Taxes: Don't Get Caught Off Guard
The IRS expects quarterly tax payments. Miss a deadline and you owe penalties. Here's the 2026 schedule and payment methods.
Macros 101: Setting Protein, Carbs and Fat Targets
Calories alone do not build muscle or fat. The split between protein, carbs and fat shapes body composition.
Typing Speed Benchmarks: What WPM is Average vs Good
Average adult typist: 40 WPM. Programmer: 50-60. Professional transcriber: 75-90. Top 1%: 120+.
JWT Decoder Demystified: What is Inside Your Auth Token
A JWT is three base64-encoded JSON blobs joined by dots: header.payload.signature. The signature is the only secret.