Guide library
Guides
Plain-English guides for common tasks: tipping, splitting bills, converting colors, comparing text, and making safer passwords.
3 guides
Calculators
Simple guides for percentages, ratios, ages, salaries, random numbers, and everyday math.
13 guides
Tipping & bill splitting
Simple guides for tips, totals, and splitting shared bills.
4 guides
Color tools
Practical explanations of web color formats, contrast, and converters.
4 guides
Developer utilities
Small browser utilities for JSON, Base64, diffs, timestamps, URLs, UUIDs, and text work.
2 guides
Writing & content
Simple guides for word counts, character limits, placeholder copy, reading time, and publishing drafts.
1 guide
Password security
Plain-English guidance for stronger passwords and safer online habits.
4 guides
Music practice
Beginner-friendly guides for tempo, timing, metronomes, stopwatches, and focused practice.
10 guides
Images & graphics
Practical guides for optimizing, cropping, resizing, and converting images for fast, good-looking websites.
6 guides
Audio & sound
Practical guides for compressing, converting, and trimming audio so it sounds good and loads fast on the web.
Start here
Popular practical guides
audio
How to compress audio for the web without losing quality
Learn how to compress audio for the web without wrecking the sound: bitrate, mono vs stereo, and a free in-browser tool to shrink files fast.
audio
How to convert WAV to MP3 for free
How to convert WAV to MP3 for free in your browser — no upload, no install. Pick a bitrate, shrink the file by up to 95%, and download.
audio
How to make an audio file smaller for email
How to make an audio file smaller for email and uploads: lower the bitrate, switch to mono, and trim — all free and private in your browser.
audio
How to trim an audio clip online for free
How to trim an audio clip online for free with a visual waveform editor — cut the part you need and export MP3 or WAV, no upload required.
audio
WAV vs MP3: which audio format should you use?
WAV vs MP3 explained in plain English: quality, file size, and when to use each — plus a free way to convert between them in your browser.
audio
What audio bitrate should you use?
What audio bitrate should you use for podcasts, music, and the web? A simple guide to kbps, quality, and file size with practical presets.
images
What is the best image size for a website hero banner?
How to size a website hero or banner image: the right width, aspect ratio, and file-size budget to look sharp and load fast — plus a free tool to make it.
images
How to compress images for the web without losing quality
Learn how image compression works, how to find the quality sweet spot, and how to shrink photos for the web without visible quality loss — for free.
images
How to make a square profile picture for free
A beginner's guide to cropping any photo into a perfect square profile picture or avatar — the right size, centering tips, and a free browser tool.
images
How to reduce image file size for email
Photos too big to email? Learn why attachments get rejected, the typical size limits, and how to shrink images for email for free without losing quality.
images
Image sizes for Instagram: posts, stories and reels
The common Instagram image sizes and aspect ratios for square, portrait, and landscape posts, stories, reels, and profile pictures — plus a free cropping tool.
images
The standard image sizes for a website (and a free tool to make them)
The common image sizes every website needs — hero, content, product, card, thumbnail, and avatar — with target dimensions and a free tool to make them.
images
WebP vs JPEG vs PNG: which image format should you use?
A plain-English comparison of WebP, JPEG, and PNG for websites — when to use each, how they differ in size and quality, and how to convert between them.
images
Why image optimization matters for website speed
A beginner's guide to why heavy images slow down websites, how it hurts visitors and SEO, and the simple steps to fix it before you publish.
color-tools
How to convert hex to RGB for CSS
Step-by-step guide to converting hex color codes to RGB for CSS, including the math, 3-digit shorthand, the modern rgb() syntax, and adding alpha transparency.
developer-tools
How to convert a Unix timestamp to a date
A plain-English guide to converting Unix (epoch) timestamps to readable dates, handling seconds vs milliseconds, and going back from a date to a timestamp.
developer-tools
What is a diff checker and when should you use one?
Learn what a diff checker does, how to compare two blocks of text online, how to read additions and deletions, and when a diff beats manual review.
music-practice
Best rhythm training apps for musicians: comparison for students
A researched comparison of rhythm-reading and rhythm-training apps, including prices, strengths, limitations, and a free browser option for beginners.
music-practice
How to practice rhythm without an instrument
Learn how to improve rhythm away from your instrument using clapping, counting, tapping, rests, a metronome, and short reading exercises.
music-practice
Rhythm reading for beginners: a mini-course on what to learn first
A step-by-step rhythm reading mini-course for beginners: pulse, quarter notes, rests, eighth notes, simple patterns, and practice levels.
writing-and-content
How many words fit in a 5-minute speech?
A practical guide to estimating 5-minute speech length, speaking pace, rehearsal time, and how many words to write.
calculators
How to convert annual salary to hourly pay
Learn the simple salary-to-hourly formula, common assumptions, and examples for 40-hour weeks, part-time schedules, and unpaid time off.
calculators
How to calculate a percentage: the simple formula
Learn the basic percentage formula with simple examples for discounts, test scores, money, and everyday numbers.
images
How to resize an image without changing its aspect ratio
Learn how to resize an image while keeping the same shape, avoid stretching, and calculate the missing width or height.
music-practice
How to use a metronome for beginners
A beginner-friendly guide to metronome practice: choosing a BPM, starting slowly, counting beats, and building steady rhythm.
calculators
Percentage increase vs percentage decrease explained
Understand percentage increase and percentage decrease with clear formulas, examples, and common mistakes to avoid.
developer-tools
Is it safe to paste JSON into an online formatter?
Learn when it is safe to use an online JSON formatter, what data you should avoid pasting, and a simple privacy checklist.
color-tools
WCAG AA vs AAA contrast: what is the difference?
Understand WCAG AA and AAA color contrast levels, what ratios they use, and which target is realistic for most websites.
developer-tools
What is a JSON formatter and when should you use one?
Learn what a JSON formatter does, why formatted JSON is easier to read, and when to use one while debugging APIs or config files.
images
What is aspect ratio? A simple guide for images and video
A simple explanation of aspect ratio for images, video, screens, and social posts, with examples like 1:1, 4:3, 16:9, and 9:16.
color-tools
What is color contrast and why does it matter for accessibility?
Learn what color contrast means, why it affects readability, and how to check whether text and UI colors are easy to see.
writing-and-content
Word count vs character count: what is the difference?
Understand the difference between word count and character count, when each one matters, and how to check both before you publish.
tipping
Tipping around the world: a practical country guide
A practical guide to tipping customs around the world, with restaurant ranges, local expectations, and links to country-specific guides.
tipping
How to calculate a tip without overthinking it
A practical, calm guide to choosing a tip percentage, calculating the total, and avoiding common tipping mistakes.
color-tools
Hex vs RGB vs HSL: what is the difference?
A plain-English explanation of hex, RGB, and HSL color formats, with CSS examples and when to use each one.
password-security
How to create a strong password in 2026
A practical guide to strong passwords, passphrases, password managers, and common mistakes to avoid.
tipping
How to split a bill with tip
A practical guide to splitting a restaurant bill with tip, tax, uneven orders, and simple rounding rules.
Travel tipping
Tipping guides by country
Tipping customs change a lot from country to country. Use these short guides before eating out, taking a taxi, staying at a hotel, or joining a tour abroad.
Tipping in Australia: when it is optional and when it makes sense
A clear guide to tipping in Australia, including restaurants, cafes, fine dining, service charges, and why tips are usually optional.
Tipping in Canada: how much to leave at restaurants
A simple guide to tipping in Canada, including restaurant ranges, tax, card prompts, service charges, and bill splitting.
Tipping in France: service compris, rounding up, and when to leave extra
A clear guide to tipping in France, including service compris, restaurant bills, rounding up, and how much extra to leave.
Tipping in Italy: coperto, servizio, and how much to leave
A practical guide to tipping in Italy, including coperto, servizio, rounding up, and when a small restaurant tip makes sense.
Tipping in Japan: why you usually should not tip
A practical guide to tipping in Japan, including restaurants, taxis, hotels, private guides, envelopes, and when not to leave money.
Tipping in Spain: when to round up and when to leave extra
A practical guide to tipping in Spain, including restaurants, tapas bars, rounding up, tourist areas, and simple percentage ranges.
Tipping in Mexico: restaurants, bars, resorts, and everyday rules
A practical guide to tipping in Mexico, including restaurant percentages, service charges, bars, resorts, and when to use cash.
Tipping in Germany: Trinkgeld, rounding up, and restaurant etiquette
A simple guide to tipping in Germany, including restaurant percentages, rounding up, cash tips, and how to say the final amount.
Tipping in the United States: restaurants, service charges, and simple percentages
A practical guide to tipping in the United States, including restaurant percentages, service charges, counter service, and bill splitting.
Tipping in the United Kingdom: service charges and restaurant etiquette
A practical guide to tipping in the UK, including discretionary service charges, when to add 10–15%, and how to read the bill.