How to Add HTML and CSS to PDF: PHP Guide with Examples

Introduction: Why HTML+CSS to PDF is a Headache (and How to Solve It)

Imagine: you're developing a website in PHP, and the client asks: "Make the 'Download PDF' button export beautiful invoices, reports, or certificates." You think: "Easy! I'll take an HTML template, add some CSS styles, and convert it to PDF." But reality turns out to be more complicated: fonts shift, tables break apart, and the CSS property flexbox works inconsistently.

On Stack Overflow, the question "How can I add HTML and CSS into PDF" has gathered thousands of views. This means the problem is familiar to almost every PHP developer. In this article, we'll cover three popular libraries — Dompdf, TCPDF, and mPDF — and show you how to properly convert HTML with CSS to PDF in PHP.

You will learn:

• Which library to choose for different tasks
• How to include CSS styles (external, inline, @import)
• How to solve common issues: Cyrillic characters, tables, images
• How to write working code for generating PDF from HTML

Why Can't You Just Save HTML as PDF?

Browsers render HTML+CSS perfectly, but PDF generators are not browsers. They use their own rendering engines that do not support all CSS properties. For example:

• flexbox and grid — don't work everywhere
• border-radius — partially supported
• @media print — may be ignored
• Fonts (especially Cyrillic) — require embedding

The good news: modern PHP libraries are constantly improving, and with the right approach, you can get a PDF that looks almost like in a browser.

Overview of Libraries for Converting HTML+CSS to PDF in PHP

Let's look at three of the most popular tools. Each has its own strengths.

1. Dompdf

Pros: lightweight, easy to install via Composer, good support for CSS 2.1 and partial CSS3. Great for simple documents — invoices, receipts.

Cons: weak support for complex layouts (flexbox, grid), issues with large amounts of HTML.

2. TCPDF

Pros: stable, powerful, supports Unicode (Cyrillic), works without external libraries. Ideal for complex PDF files with charts, QR codes, multi-page tables.

Cons: complex syntax, CSS styles need to be included manually, code can be bulky.

3. mPDF

Pros: best CSS support (including @media, float, position), excellent Cyrillic support, supports styles from external files. Considered the "sweet spot".

Cons: heavier than Dompdf, can be slow on large documents.

Recommendation: For a quick start, use Dompdf. For serious projects — mPDF. TCPDF — if you need maximum flexibility and are willing to write more code.

Practical Example: Generating PDF from HTML with Dompdf

Let's write some real code. Install Dompdf via Composer:

composer require dompdf/dompdf

Now create a PHP script that converts an HTML template to PDF:

<?phprequire_once 'vendor/autoload.php';

use Dompdf\\Dompdf;use Dompdf\\Options;

// Settings$options = new Options();$options->set('defaultFont', 'DejaVu Sans'); // Cyrillic support$options->set('isRemoteEnabled', true); // Allow external images

$dompdf = new Dompdf($options);

// HTML template$html = '<!DOCTYPE html><html><head>    <style>        body { font-family: DejaVu Sans, sans-serif; }        .invoice {            width: 100%;            max-width: 80