Online Tools Guides & Tips
Health, finance, office, developer and design know-how — each guide paired with free online tools you can use right away.
Do the Math First: BMR, Heart-Rate Zones and Daily Calories Explained
Before any diet, know your numbers: basal metabolic rate, TDEE, fat-burning heart-rate zones, exercise calories and daily water needs — calculated in minutes.
2026-10-01 · 5 min read →
Three Calculations Before Signing a Mortgage: Payments, Interest and Compounding
Equal-payment vs equal-principal loans, how monthly payments are computed, whether early repayment pays off — plus the Rule of 72 and the true discount of bundle deals.
2026-10-01 · 6 min read →
From Gross to Net: How Salary Deductions and Income Tax Work
Why does your payslip never match the offer letter? Social insurance, housing fund, tax brackets and special deductions explained — plus RMB amount-in-words rules for invoices.
2026-10-01 · 5 min read →
Ages, Due Dates and Deadlines: Date Math You Actually Use Weekly
Full age vs traditional age, why a due date is 280 days, and how to count working days between dates — everyday date calculations done right.
2026-10-01 · 4 min read →
Unit Conversion Cheat Sheet: Mu, Liters, Gigabytes and MPH
How big is a mu of land, why does a 1TB drive show 931GB, what does 'mai' mean on the highway — the conversions that trip people up, in one place.
2026-10-01 · 4 min read →
Compare, Clean, Analyze: A Text Processing Workflow for Everyday Work
What changed between two drafts, dedupe a 5,000-line list, check keyword density — practical uses for diff, dedupe, replace and word frequency tools.
2026-10-01 · 5 min read →
The Developer's Browser Toolbox: JSON, JWT, Hashes and Regex
Reading minified API responses, decoding tokens, verifying file integrity — the high-frequency dev chores solved locally in the browser.
2026-10-01 · 5 min read →
Pomodoro Done Right: The Science of 25 Focused Minutes
The Pomodoro Technique is more than a timer: rules, why 25 minutes works, handling interruptions, and adjustable variants that keep the rhythm.
2026-10-01 · 4 min read →
White Noise Explained: Why It Aids Both Sleep and Focus
White vs pink vs brown noise, which scenarios each fits, how loud is too loud — used well it's a focus superpower, used badly it's ear strain.
2026-10-01 · 4 min read →
Raffles, Roll Calls and Team Drafts: Using Random Tools Fairly
How to call on students without repeating names, split a team with zero politics, replace lost board-game dice — the fair way to use online randomizers.
2026-10-01 · 4 min read →
Lunar Calendar Explained: Converting Dates, Zodiac & Constellations
How does the Chinese lunar calendar map to Gregorian dates? What about leap months, zodiac animals and constellation signs? Clear answers to the most confusing questions.
2026-09-30 · 5 min read →
Scheduling Cross-Timezone Meetings Without Pain
Time difference cheat sheet for major cities, daylight-saving traps, and three golden rules for picking meeting times that nobody hates.
2026-09-30 · 5 min read →
CSS Gradients, Shadows & Border Radius: The Details That Scream Quality
Why do some buttons look premium and others cheap? Practical numbers for gradients, box-shadow, border-radius and colors — copy-ready rules, no theory.
2026-09-30 · 5 min read →
Stop Buying the Wrong Size Online: Shoe & Clothing Size Guide
How to measure your foot, convert CN/EU/US shoe sizes, and what S/M/L actually means — buy the right size the first time and cut your return rate in half.
2026-09-30 · 4 min read →
How to Type Faster: From Hunt-and-Peck to Touch Typing
Typing speed is a method problem, not a talent problem. Speed tiers, a 3-step touch typing plan, and a 15-minute daily routine that shows results in two weeks.
2026-09-30 · 4 min read →
Fuel Costs and Tipping: The Travel Math Nobody Explains
The fuel consumption formula done right, tipping customs by country, and splitting group bills in one click — all the travel arithmetic in one place.
2026-09-29 · 5 min read →
HTTP Status Codes Explained: What 404, 502 and 503 Really Mean
A website won't load — whose fault is it? Quick reference for 200, 301, 403, 404, 500, 502, 503: what each means, who is responsible and what to do.
2026-09-29 · 6 min read →
Why URLs Contain %20: Encoding, Decoding and Other Everyday Mysteries
Percent signs in links, garbled characters after paste, Base64 and UUID in developer talk — what each encoding is actually for, in plain language.
2026-09-29 · 5 min read →
Office Light: E-Signatures, Quick Notes and To-Dos in the Browser
Sign a document, capture a thought, organize today's tasks — lightweight office tools that run in your browser, keep data local and never upload a byte.
2026-09-29 · 4 min read →
Inside an 18-Digit Chinese ID Number: Structure and Checksum
What each segment of an 18-digit ID means, why some end with X, and how the checksum works — the developer's guide to form validation (format only, privacy respected).
2026-09-29 · 4 min read →
How to Compress Images Without Losing Quality (2026 Guide)
Learn how to compress JPG, PNG and WebP images to the smallest file size with minimal quality loss. Quality settings, format choice and per-scene recommendations — all explained simply.
2026-09-28 · 6 min read →
PNG vs JPG vs WebP: Which Image Format Should You Use?
A complete comparison of PNG, JPG and WebP: compression, transparency, file size and best use cases — so you always save images in the right format.
2026-09-28 · 5 min read →
How to Watermark Photos to Protect Your Copyright
Stop image theft: where to place watermarks, the ideal opacity, tiled and diagonal patterns that can't be cropped out, plus a free way to watermark photos online.
2026-09-28 · 5 min read →
How to Create a QR Code for URLs, WiFi and Business Cards
Create QR codes for free: link QR codes, WiFi QR codes and vCard contact codes explained, plus design tips to maximize scan rates.
2026-09-28 · 4 min read →
How to Resize Images for Web, Email and Social Media
Oversized photos failing to upload? Learn the three levers of image size — dimensions, format and quality — with recommended pixel sizes for every common use.
2026-09-28 · 4 min read →
Image Cropping Guide: Crop Like a Pro for Portraits, Avatars and Products
Cropping is recomposition: ID photo standards, avatar framing, e-commerce hero image rules — practical cropping tips that make ordinary photos look professional.
2026-09-28 · 5 min read →