Guides

Step-by-step guides on PDFs, salary and tax calculations, image editing, security and developer topics, with worked examples and common mistakes.

How to Edit PDF Files: A practical guide to choosing and using PDF tools.
10 Ways to Work More Efficiently with ChatGPT: Improve your AI use in daily workflows.
How to Choose the Best AI Tools: A checklist for picking the right AI tool for your needs.
Cloud Storage Comparison: Compare popular cloud storage options.
How to Edit a PDF Downloaded from e-Devlet: A practical guide to editing official Turkish government PDFs without breaking them.
How to Calculate 2026 Income Tax in Turkey: How Turkey's bracket-based income tax actually works.
2026 Severance Pay Calculation Guide (Turkey): Getting full-year and partial-year severance calculations right.
VAT Calculation: Included or Excluded?: How to stop mixing up VAT-included and VAT-excluded amounts.
Extracting Invoice Data from PDF to Excel: Digital and scanned invoices need different approaches.
Social Media Image Size Guide (2026): Choosing the right ratio for each platform.
How to Build a Hashtag Strategy: Why relying only on popular tags doesn't work.
How to Read Your Core Web Vitals Results: Each of the three metrics points to a different problem.
What Is JSON and What Is It For?: A beginner's look at the basic structure, with a first example.
What Is a JWT and How Do You Decode One?: The difference between decoding and verifying.
What Is a UUID and When Should You Use One?: Why choose a UUID over a simple incrementing ID.
A Beginner's Guide to Writing Regex: A handful of core symbols cover most everyday needs.
How to Build a Strong Password Policy: What actually works, beyond piling on complexity rules.
How to Write an SEO Meta Description: It won't move your ranking, but it moves your click-through rate.
What Are Open Graph Tags and Why They Matter: The tags that decide how a link looks when shared.
How to Create a robots.txt File: The difference between blocking crawlers and hiding from search.
What Is sitemap.xml and How Do You Submit It to Google?: The file that gets new pages discovered faster.
Image Compression: Smaller Files Without Losing Quality: The difference between lossless and lossy compression.
Background Removal: Automatic or Manual Touch-Up?: Where automatic tools shine, and where they struggle.
How to Write a Cron Expression: Getting the order of the five fields right is the key part.
The Confusing Part of Converting Net Salary to Gross: You said "I want 40k net" in the interview, the employer offered a gross number. Now what?
Notice Pay and Severance Pay Are Not the Same Thing: Mixing these two up when leaving a job is extremely common, but they're paid under different conditions and different amounts.
Am I Covered by EYT? A Short Roadmap: Your insurance start date matters more here than you might think.
How Much Annual Leave Are You Actually Entitled To?: 14 days, 20 days, or 26, it depends on your seniority, and most people have it wrong.
Is Your Overtime Pay Being Calculated Correctly?: Finding your hourly rate is a simpler division than you'd think, but this step gets skipped in a lot of payslips.
Where Do Those Weird "Ã§" Characters Come From?: Seeing Ã§ instead of ç when you open a file is annoying, but there's actually a pretty logical reason for it.
How Do You Clean a PDF's Hidden Metadata?: A practical way to remove the invisible author name, edit dates, and other metadata a PDF carries when you share it.
PNG, JPG, or WebP? How to Choose an Image Format: A practical comparison of when each format actually gives you a better result.
How Do You Actually Create a Strong Password?: Practical advice on length, randomness, and using a password manager.
Why Formatting JSON Properly Saves You Time: Why debugging unformatted JSON is harder than it needs to be.
Are QR Codes Always Safe to Scan?: What to watch for in your QR code scanning habits.
Common Mistakes When Calculating VAT: Practical warnings about gross/net mix-ups and rounding mistakes.
What Changed in 2026 for Social Media Image Sizes: A practical summary of the sizes platforms currently recommend.
How to Shorten a Text Without Losing Its Meaning: The difference between summarizing and paraphrasing.
When Are Shortened Links Risky?: What to watch for when a link-shortening service hides the real destination.
How Do You Read a Cron Expression by Hand?: Understanding scheduled-task syntax step by step.
How to Convert HEIC Files to JPG: Why iPhone's default format won't open in most places, and the practical fix.
How to Validate an IBAN Number: How to check whether an IBAN is valid before sending money.
How to Reduce PDF File Size Without Losing Quality: The right way to shrink a PDF that's too big to email.
Converting Excel to CSV and CSV to Excel: Why the two formats aren't interchangeable, and what gets lost in the conversion.
What Is Base64 Encoding and When Should You Use It?: It's not encryption, it's a transport format — how to tell the two apart.
What Is Markdown and How Do You Use It?: The basics of the lightweight formatting language you'll see on GitHub, Notion, and beyond.
HEX, RGB, HSL: The Difference Between Color Codes: The logic behind writing the same color three different ways.
A Timezone Guide So You Stop Miscalculating Meeting Times: Daylight saving time changing on different dates in different countries is what actually causes the confusion.
Free Invoice Tools for Freelancers: Putting together a quick invoice or quote without needing full accounting software.
Can an Online-Generated Signature Image Be Used on Official Documents?: A practical guide clarifying the difference between a visual signature image and a legally valid e-signature.
How to Convert Between Fahrenheit and Celsius: The quick way to make sense of Fahrenheit values you'll see in US sources.
A Guide to Not Getting Lost Between Imperial and Metric Units: How to quickly find the metric equivalents of miles, pounds, and inches.
Is 01/02/2026 January or February? A Guide to Date Format Confusion: The US writing dates in a different order than most of the world causes real mix-ups.
What to Do When You Hit Gmail or Outlook's Email Attachment Size Limit: Two simple routes to take, without panicking, when you hit the 25 MB wall.
What to Watch for When Invoicing a Client Abroad: Currency, date format, and language can all cause confusion at once.
Social Media Character Limit Checker: Check your text against X, Instagram, LinkedIn, Facebook, TikTok and YouTube character limits for free.
Email Format Checker: Instantly check whether an email address is formatted correctly, for free, right in your browser.
Rent Increase Calculator: Calculate your new rent amount from the increase rate, free. Includes a link to the official Turkish CPI data source.
Does Compressing a PDF Reduce Quality?: Learn how PDF compression affects image and text quality, when quality loss actually happens, and how to avoid it.
Invoice vs. Receipt: What's the Difference?: Learn the difference between an invoice and a receipt, and which one you should ask for and when.
How Do Income Tax Brackets Work?: Learn how Turkey's progressive income tax bracket system works and where to check the current thresholds.
QR Code vs. Barcode: What's the Difference?: Learn the data-capacity and use-case differences between QR codes and barcodes, and which one fits your need.
How to Calculate Percentages: Formulas and Everyday Examples: Discounts, pay rises, tax or test scores: the four basic percentage formulas and the most common mistakes, with worked examples.
How Loan Payments Are Calculated: Interest, Term and Total Cost: The monthly payment formula for fixed-instalment loans, how the term changes total interest, and what to compare between offers.
How to Count the Days Between Two Dates: Should the end day count, how is a month difference found, and why are business days different? A practical guide for contracts, leave and deadlines.
How to Calculate a Weighted Average (Grades and More): Credit-weighted grade averages, midterm and final weightings, and how they differ from a simple average, with step-by-step examples.
How to Create a QR Code: A Guide for Menus, Wi-Fi and Links: Size, contrast and testing when you make a QR code, the text format used for Wi-Fi networks, and what to check before printing.
How Two-Factor Authentication (2FA) and TOTP Codes Work: Where the 6-digit codes in authenticator apps come from, how they differ from SMS, and why backup codes matter. A practical guide to protecting your accounts.
What Is BMI and How Is It Calculated?: The BMI formula, the World Health Organization categories, and what the index does and does not tell you; it is not a health measure on its own.
How to Merge and Split PDF Files: Page Order, Ranges and Tips: Steps for combining several PDFs into one or pulling specific pages out of a PDF, how to write page ranges, and common problems.

Who are these guides for?

For anyone doing a task for the first time, or anyone who keeps having to look up how to do something and wants to finish it faster. Each guide focuses on one question: how to shrink a PDF, how loan payments are calculated, how to create a QR code. Alongside the steps you will find common mistakes and examples worked through with real numbers.

How are the guides written?

Each guide is written while looking at the actual screen of the tool it describes, and never claims a tool does something it cannot. For figures that change, such as tax brackets or legal deadlines, official sources are the reference and the year they apply to is stated. When the rules change, the guide is updated. The details are in our Editorial policy.

Where to start

The list covers PDF and document tasks, salary and tax calculations, image editing, security and developer topics. At the end of each guide you will find links to the related tools, so you can try what you have just read. For shorter posts on everyday topics, see the Blog.