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 can run yourself.
You have a 38 MB PDF to drop into a form that refuses anything over 10 MB. You type “compress PDF”, three services fill the top of the page, and they all look alike: a drop zone, a button, a file coming back. By the third attempt you still don’t know which one to keep.
What separates Convertu, Smallpdf and iLovePDF is not the feature lists: those overlap heavily. It is four concrete things — where the file is actually processed, what stays on a server afterwards, when you are asked for an account, and what the service does with the awkward cases. Here is how to judge them yourself, and where Convertu sits.
Where the file is processed: your browser or a server
This is the most decisive difference of the three, and the least advertised. A modern browser can handle a good share of the work on its own. Resizing, cropping, rotating, compressing an image, generating a QR code, computing an MD5 or SHA hash, encoding to Base64, formatting JSON or CSS, counting words: all of that runs in JavaScript and WebAssembly inside the open tab. Not a single byte leaves your machine.
Other jobs are too heavy for the browser, or too expensive to ship inside a web page: video re-encoding, HEIC decoding, subject detection to remove a background, converting a PDF into an office format. At Convertu, those go through a server.
Of Convertu’s 60 tools, 41 run entirely in the browser and 19 go through the server — the PDF and video families, HEIC conversion, background removal, image blurring and watermarking, the HTML validator. Smallpdf and iLovePDF, for their part, were built around PDF, a format that largely forces remote processing, so the question plays out differently for them.
The test takes thirty seconds. Open the developer tools (F12), go to the Network tab, then start the conversion. If a request goes out carrying a body roughly the size of your file, your file is on a server. If the only traffic is the scripts loaded when the page opened, it has not moved.
A specialised PDF suite or a general toolbox
Smallpdf and iLovePDF are suites centred on PDF and its ecosystem: deep document tooling, desktop apps, connectors to online storage. Check the exact scope as you read this, because it moves fast.
Convertu takes the opposite approach: PDF is only one family out of seven. Image, video and audio, text, calculators, web tools and assorted converters make up the rest of the catalogue.
The consequence is very practical. If your week means compressing a PDF on Monday, pulling the audio track out of an MP4 on Thursday, converting iPhone HEIC photos at the weekend and checking some JSON in between, a PDF suite leaves you halfway there and you end up opening a tab somewhere else. If, on the other hand, you live in documents all day, with demanding needs around forms, annotation or signing, a specialist will take you further than a generalist.
What “free” means, in detail
There are four ways to restrict a free version, and they are not equivalent:
- an operations quota per hour or per day;
- a size cap on the file or on the number of pages;
- a watermark stamped onto the result;
- the obligation to create an account before you can retrieve the file you produced.
At Convertu, 36 of the 41 tools that run in the browser need neither an account nor a quota: the work happens on your own machine, so it costs nobody anything. The other five — image compression, resizing, format conversion, cropping and rotation — are local too, but they ask for an account and belong to the subscription. The 19 server tools offer one conversion per visitor per day, with no sign-up. Beyond that, unlimited access comes through a single subscription at €7 a year, with no minimum term.
Measure what you actually need before you compare. Compressing a PDF before you send it is a one-off. Handling forty scans a month is a recurring job: at that rate the question is no longer the headline price, but which limit will block you first.
Retention, encryption, jurisdiction
Three questions apply to any online converter.
| Question | What you are looking for |
|---|---|
| How long does the file stay on the server? | A retention period stated in black and white. At Convertu, uploaded files are deleted after one hour. |
| Is the transfer encrypted? | HTTPS across the whole chain, including the page you download the result from. |
| Who runs the service, and under which law? | An identifiable entity. Convertu is operated by SOLUTION AS A SERVICE, in Brussels, so under the EU’s GDPR. |
A useful habit: a contract, a payslip or a client quote has no reason to travel through a third-party server when the job can be done locally. Cropping, compressing an image and counting words all belong in the browser.
The pitfalls that decide how good the result is
Comparing feature lists gets you nowhere until you know the four or five cases that defeat any converter.
PDF to Word
A native PDF, produced from a word processor or a page-layout application, contains vector text: the conversion recovers the words, but only approximates the layout — columns turned into text boxes, tables recreated imperfectly. A scanned PDF, by contrast, contains nothing but images: without character recognition, no tool will hand you editable text, only one photo per page pasted into a document. The check takes a second: if you can select the text in your PDF reader, it is native. If not, an OCR step comes first, before you convert the PDF into a Word document.
The second pitfall in the same job: fonts that are not embedded in the file. They get swapped for near equivalents, the line breaks shift, and a twelve-page document sometimes comes out with thirteen.
PDF compression
In a heavy PDF, most of the weight comes from the images, not the text. A scan saved at 600 DPI comes down to 150 DPI with no visible damage for reading on screen, or 200 to 300 DPI if the document is going to be printed: that drop to screen resolution is what takes a 38 MB file below the 5 MB mark when you compress the PDF. On a document made purely of vector text, on the other hand, the gains are marginal — there is simply nothing to compress, and no service will do better than another.
Images
In JPEG, a quality setting of 80 to 85 is the right compromise for the web; below 70, the artefacts become visible on flat areas of colour and around text. Another point worth knowing before you bring an image’s file size down: JPEG has no alpha channel. A PNG with a transparent background converted to JPEG comes out on a black or white background, without warning. To keep transparency, stay in PNG or move to WebP.
Finally, iPhone photos saved as HEIC are refused by plenty of platforms and applications. Converting to JPG settles that, but bear in mind that EXIF metadata — date, camera model, GPS coordinates — is often preserved through the conversion, depending on the tool used. Check the file you get back and strip that metadata if the image is going onto a public site, a point to watch when you turn your HEIC files into JPG.
Which service for which situation
- You live in PDFs — forms, annotation, signing, several people working on the same documents: take a specialist in the format, possibly one with a desktop app.
- Your needs are varied and irregular — a PDF, then a video, then some photos, then text: a broad catalogue saves you juggling accounts and tabs.
- Your documents are sensitive: always favour processing that stays inside the browser, and verify it instead of taking it on trust.
- You convert two or three files a month: the free daily conversion is enough, there is no need to pay for anything.
- You convert every week: think in annual cost rather than the monthly headline price, and read the cancellation terms before you commit.
On that last point, Convertu made a simple choice: a single subscription at €7 a year opens the 19 server tools and the five local image tools with no limit, it can be cancelled in one click, and the other 36 browser tools remain free to use.