Convertu Blog
How-tos, comparisons and tips.
20 online tools that replace installed software — and the one setting to know for each
Twenty utilities that sort out an unreadable HEIC, a PDF too large for a form or a 450 MB video, and the one setting to check on each.
Convertu vs Smallpdf vs iLovePDF: the 2026 comparison
All three make the same promises. Here are the four technical criteria that genuinely tell them apart, and the 30-second test you…
€7 a year: what the Convertu subscription actually pays for
Why 41 Convertu tools cost nothing to run, why the other 19 cost real money, and what your €7 a year actually pays for.
How to convert a PDF to Word for free
A PDF contains no paragraphs and no tables: knowing what the converter has to rebuild explains every flaw in the .docx you get ba…
How to compress a PDF without losing quality
An oversized PDF nearly always has one culprit — the images. Here are the settings that cut its weight without visibly degrading …
Merging multiple PDFs into a single file
Combining six documents into one PDF rarely fails at the merge itself — it fails on file order and on the final file size.
Compress an image without visible loss of quality
Why you should cut the pixel dimensions before touching the quality slider, and the point at which JPEG compression really starts…
Password-protecting a PDF
A PDF can carry two kinds of password, and only one of them really protects anything: which to choose, and the mistakes that canc…
Convert HEIC to JPG on Windows and Mac
Your iPhone's .heic files stay unreadable for plenty of software and upload portals. Here is how to get clean JPGs, with orientat…
Converting a PDF to an image (JPG, PNG)
JPG or PNG, 150 or 300 DPI, text that turns into pixels: the settings to get right before you export the pages of a PDF.
Creating a QR code: URL, Wi-Fi, vCard and the settings that matter
Quiet zone, error correction, contrast, Wi-Fi syntax: what separates a QR code that scans from a decorative square.
Generate a secure password
Why a “complex” eight-character password is weaker than sixteen randomly drawn characters, and how to set the generator up.
Resizing an image online: dimensions, ratio and quality
Pick the right pixel dimensions, keep the aspect ratio and avoid a white block where your PNG transparency used to be.
Converting PNG to JPG: transparency, quality and file size
A screenshot saved as PNG can be ten times heavier than an equivalent JPEG. Here is when converting pays off, and what you lose d…
Reducing a photo's size to send it by email
Resize first, compress second: the method for taking a 5 MB photo down to 300 KB with no visible artefacts.
Base64: encoding, decoding and the traps to avoid
Three details account for nearly every Base64 failure: the character set, the alphabet in use and the padding. Here is how to spo…
Computing an MD5 or SHA hash without getting it wrong
Two digests that refuse to match are almost always one invisible byte: a trailing line break, a UTF-8 BOM or a different encoding.
Counting words and characters online
The same text rarely produces the same total from one tool to the next. Here is what sits behind each figure.
Currency conversion: which exchange rate actually applies
The rate a converter shows you is almost never the one your bank applies. Here is how to measure the gap for yourself.
Working out VAT: net, gross and rounding to the penny
Subtract 20% from a gross figure and you will not land on the net one. The exact formulas, UK rates, the VAT fraction and the pen…
Working out your BMI: formula, bands and limits
Weight over height squared. Simple enough — until the centimetres, the stones and the WHO cut-offs trip everyone up.
Converting time zones without getting it wrong
Why CST, PST and “GMT+1” make people miss meetings, and how to convert a time between two cities without ending up an hour out.
Working out the difference between two dates without being a day out
Why the same stretch of calendar comes out as 91 days for one person and 92 for another, and how to reach the figure that will st…
Convert an MP4 to MP3 without ruining the sound
Which bitrate to choose, why an MP3 pulled from a video always sounds quiet, and how to avoid compressing twice.
Compress a video for WhatsApp without going over 16 MB
WhatsApp caps videos at 16 MB and re-encodes everything anyway: here is the bitrate to aim for at each length, without ending up …
Extracting audio from a video
Pulling the soundtrack out of an MP4 or MKV without degrading the signal: which format to pick, which bitrate, and the traps wort…
Online file security: good habits worth keeping
How to tell whether a converter really uploads your file, and what to check before you hand it a document you care about.
10 Excel shortcuts that save you real time
Ten Excel keyboard shortcuts that replace whole minutes of mouse work, with Mac equivalents and the reasons each one sometimes do…
How to optimise images for the web
A 4 MB photo on your home page costs seconds of loading time. Here is how to bring it down to 150 KB with no visible loss.
Productivity: automating your repetitive tasks
Four minutes twice a week is close to seven hours a year: how to spot, standardise and occasionally script your routines.