Learn
Every guide on the site, grouped by what it is about.
Images
- Why won't my favicon update?Browsers cache favicons harder than anything else on a site. Which sizes you actually need, and why the .ico file still matters in 2026.Favicon generator · 3 min
- Why did my animated GIF become a single still image?PNG holds one frame, so an animation converts to its first frame only. What to do if you wanted the movement, and what to do if you wanted one picture.GIF to PNG · 3 min
- What is a HEIC file, and why will it not open?HEIC is the format iPhones save photos in. Windows and older software often cannot read it. Here is why, and the three ways to fix it.HEIC to JPG · 3 min
- Which image format should you actually use?JPG for photos, PNG for graphics, WebP for the web. Here is why, and why compressing a photo to PNG makes it bigger.Image compressor · 4 min
- What size should I resize an image to?Match the space it will sit in, then double it for high density screens. Why enlarging never works, and what the aspect ratio is doing.Image resizer · 3 min
- Does converting a JPG to PNG improve the quality?No. The damage is already in the pixels and PNG just stores them faithfully, at a much larger size. Here's when the conversion is still worth doing.JPG to PNG · 3 min
- Why did my PNG turn black when I saved it as JPG?JPG has no transparency, so anything see-through has to become a colour. Black is the usual default. Here's how to control what it becomes.PNG to JPG · 3 min
- Should you convert PNG to WebP?WebP is usually 25 to 35 percent smaller than PNG with no visible difference. When it helps, when it doesn't, and what breaks.PNG to WebP · 3 min
- What is an SVG, and why does it go blurry when you export it?An SVG has no resolution until you give it one. Pick the wrong number on export and it turns soft. Here is how to choose.SVG to PNG · 3 min
- Does a watermark actually stop people using your photo?No. It makes casual reuse inconvenient and credits you when the image travels. What it can't do, and where to place it so cropping doesn't defeat it.Watermark an image · 3 min
Documents
- Why won't my PDF get smaller?Most PDFs are big because of the pictures inside them. Which of the two methods to use, and what flattening quietly destroys.Compress PDF · 3 min
- How do you open a Word file without Word?The document is converted to a PDF and shown here. What survives, what doesn't, and why this one tool sends your file to a server when the rest don't.DOCX viewer · 3 min
- Why does my spreadsheet split across pages when I convert it?Because a sheet has no page size and a PDF does. Set the print area and orientation in the spreadsheet first, since a converter can only follow what's already there.Excel to PDF · 3 min
- Why can't I type into this PDF form?Plenty of forms are just a picture of a form with no fields in them. How to tell the difference, and whether to flatten your answers.Fill a PDF form · 3 min
- Why does my web page look different as a PDF?Because a page has no fixed width and a PDF does. What print stylesheets control, why a saved page loses its images, and when the browser's own export is better.HTML to PDF · 3 min
- How do you turn a set of photos into one PDF?Drop them in, drag them into order, download one file. Why page size and orientation matter, and what to do about photos that come out sideways.Images to PDF · 3 min
- How do you turn photos into one PDF to send?Add them, put them in order, download one file. Why the result is enormous, why photos land sideways, and what page size does to printing.JPG to PDF · 3 min
- What happens to bookmarks and form fields when you merge PDFs?Page order, file size and the things that don't survive a merge. What to check before you send the combined file.Merge PDF · 3 min
- What resolution should you export PDF pages at?150 dpi for screens, 300 for print. Why the pages come out soft at the default, and when JPG is the wrong choice for a page of text.PDF to JPG · 3 min
- What resolution should I export PDF pages at?150 dpi for reading on a screen, 300 for printing. Why PNG suits documents and JPG suits scans, and what page size has to do with it.PDF to PNG · 3 min
- Why does the text come out with no line breaks, or not at all?A PDF stores positioned fragments rather than paragraphs, so line breaks are guessed. And a scan has no text in it at all, which needs recognition instead.PDF to text · 3 min
- How do you read a PDF without installing anything?Open it here and read it a page at a time or scroll the whole thing. Why it stays on your machine, and what a viewer can and can't tell you about a file.PDF viewer · 2 min
- How do you open a PowerPoint without PowerPoint?The deck is converted to a PDF and shown slide by slide. What survives, what doesn't, and why this tool sends your file to a server when the rest don't.PPTX viewer · 3 min
- Is a drawn signature on a PDF legally binding?In most countries yes, for most everyday documents. What a drawn signature actually is, and when you need a certificate-based one instead.Sign PDF · 3 min
- How do you take a few pages out of a PDF?Pick the pages you want and save them as a new file. What splitting keeps, what it drops, and why the result can be bigger than you expect.Split PDF · 3 min
- What's the difference between a PDF password and PDF permissions?PDFs have two locks. One stops the file opening, the other only asks politely. Which this removes and which it can't.Unlock PDF · 3 min
- Why does my Word document look different as a PDF?Fonts you have and the converter doesn't are the usual reason a converted document reflows. Here's what shifts, what doesn't, and how to stop it.Word to PDF · 3 min
Data
- What happens to numbers and empty cells when CSV becomes JSON?A CSV has no types, so every conversion has to guess. What gets treated as a number, what becomes null, and the leading zero problem.CSV to JSON · 3 min
- How do you open a CSV that Excel won't handle?Large files open here without waiting, and nothing gets silently reformatted. What Excel changes about your data, and how to read a file with the wrong separator.CSV viewer · 3 min
Text
- Is Base64 a way of encrypting something?No. It's a way of writing binary data as plain text, and anyone can reverse it instantly. What it's actually for, and why it makes files bigger.Base64 encoder · 3 min
- What are camelCase, snake_case and kebab-case for?Each convention belongs somewhere specific, and mixing them is how a codebase gets confusing. Which to use where, plus what title case actually capitalises.Case converter · 3 min
- How accurate is reading text from a picture?A clean scan reads almost perfectly. A photo taken at an angle reads badly, and handwriting mostly doesn't work. What to change to get a better result.Image to text · 3 min
- Should you design with lorem ipsum or real text?Real text where you can get it, because placeholder text hides problems that only appear when the words have meaning and awkward lengths.Lorem ipsum generator · 2 min
- Why does my sorted list put 10 before 2?Because it's sorting text, not numbers, and in text 1 comes before 2. What alphabetical order does to numbers, capitals and accents, and how to work around it.Sort lines · 3 min
- How do you get plain text out of HTML?Paste the markup and the text comes out. What happens to line breaks, why script contents must go, and when a regex is the wrong way to do this.Strip HTML tags · 2 min
- Why did my link break when it had a space in it?Spaces aren't allowed in a URL, so they become %20. Which characters need encoding, and the common mistake of encoding the whole link.URL encoder · 3 min
- Why do word counts disagree between tools?Hyphens, contractions and numbers get counted differently everywhere. What counts as a word here, and what the reading time is based on.Word counter · 3 min
Media
- Does trimming audio lose quality?Not if the format stays the same, because the file is cut rather than re-encoded. Changing format is what costs quality, and MP3 has one quirk worth knowing.Audio trimmer · 3 min
- How do you work out the tempo of a track by ear?Tap along for about eight beats. Why the reading settles rather than jumping, what the spread figure tells you, and the halving mistake everyone makes.BPM tapper · 3 min
- Why is my GIF bigger than the video it came from?GIF is a format from 1987 with no motion compression, so every frame is stored almost whole. What to change to get it down, and when to send video instead.MP4 to GIF · 3 min
- Why do my subtitles drift out of sync?A constant offset is one fix and a growing gap is another. Shifting handles the first, frame rate handles the second, and telling them apart takes ten seconds.Subtitle shifter · 3 min
- What does movable doh actually mean?Doh is whichever key you're in, so the same tune has the same solfa in every key. Why that makes solfa useful, and what the marks and vowels are doing.Tonic solfa converter · 3 min
- How do you make a video small enough to send?Resolution first, then quality. Why a phone video is enormous, what the limits actually are, and how long compressing takes in a browser.Video compressor · 3 min
- What bitrate should I pick when pulling audio out of a video?Converting never adds quality back. How to tell what the video already has, and why a higher bitrate than the source only wastes space.Video to MP3 · 3 min
Developer
- Why did my cron job run every minute instead of every hour?Almost always an empty first field or a missing minute value. What the five fields mean, and the mistakes that make a job fire far more often than intended.Crontab generator · 3 min
- How do you compare two versions of a text?Paste both and the changed lines are highlighted. Why whitespace and line endings cause false differences, and what a line diff can't show you.Diff checker · 3 min
- Why is my JSON invalid?Trailing commas, single quotes and comments are the usual three. What the line and column number is telling you, and how to read it.JSON formatter · 3 min
- Why does my regex match more than I expected?Usually greedy quantifiers taking everything up to the last match instead of the first. How to make them lazy, and the patterns that hang the browser.Regex tester · 3 min
Security
- Base64 is not encryption, and what it is actually forBase64 makes binary data survive text-only channels. Anyone can decode it instantly, so it hides nothing. Here is when to use it.Base64 encoder · 3 min
- What is a checksum, and why does mine not match?A hash is a fingerprint of a file. If yours differs from the published one, the usual cause is the wrong algorithm, not a tampered download.Hash generator · 3 min
- Are generated passwords actually random?It depends entirely on where the randomness comes from. Math.random is predictable. This uses the browser's cryptographic source instead.Password generator · 3 min
Calculators
- How much of the final figure is growth and how much is my own money?Usually less growth than people expect over short periods and more over long ones. Why the estimate is optimistic, and what it leaves out.Compound interest · 3 min
- Why do two date calculators give different answers?Because one counts the first day and the other doesn't. Which convention to use for notice periods, deadlines and ages, and where months get slippery.Date calculator · 3 min
- Why is my monthly payment more than the loan divided by the months?Because you're paying interest on what's still owed, and early on that's almost all of it. What the schedule shows, and why overpaying early saves so much.Loan calculator · 3 min
- How do you split a bill that won't divide evenly?Someone pays a penny more. Which is fine, and better than the alternative of everyone rounding down and the total coming up short.Tip and bill splitter · 3 min
- Why does a new 1TB drive show up as 931GB?Nothing is missing. Manufacturers count a gigabyte as 1000 megabytes and operating systems mostly count 1024, so the same drive gets two honest numbers.Unit converter · 3 min
Generators
- What size should a placeholder image be?Whatever the real picture will be. The sizes worth knowing for social, ads and layouts, and why a hotlinked placeholder service is a bad dependency.Placeholder image generator · 3 min
- Why won't my printed QR code scan?Printed too small, blown up from a small PNG, or too little contrast. What each setting does and which file to take for print.QR code generator · 3 min
- What counts as a good typing speed?Around 40 words a minute is average, 65 to 75 is a fast office typist. Why a word is five characters, and why accuracy matters more than speed.Typing speed test · 3 min
Design
Web
- Why do domain checkers disagree about whether a name is free?Most of them ask DNS, which doesn't know who owns a name. This one asks the registries. Here's the difference and where it still can't answer.Domain name checker · 3 min
- Why doesn't Google show the description I wrote?Google rewrites descriptions about two thirds of the time, usually because the page has a better answer in it. What each tag does and which lengths matter.Meta tag generator · 3 min
- Why did my site disappear from Google overnight?Usually one line. Disallow slash in robots.txt hides everything, and it normally arrives by being copied from a staging server.Robots.txt generator · 3 min
- Why does one campaign show up as four rows in analytics?Because Email and email are different mediums. UTM values are case sensitive, and inconsistent tagging splits one campaign into several.UTM link builder · 2 min