Font size tester, private browser text preview

A font size tester lets you paste actual text. Adjust the type. And check color contrast.

But You can copy the CSS instead of guessing from a mockup. Font Size Pro is a private browser tool made for this exact task:.

It shows your text live as you change size, px, line height, letter. Spacing, px, text color, and background. That’s it.

Open the private font size tester whenever you want to quickly see. If your UI text, article intro, button. Label, or help text is easy to read before publishing.

You can use the tool free for up to 20,000 characters. And it runs entirely in your browser.

It also keeps your data private, nothing leaves your device.

Here’s important if you’re reviewing draft prodcut copy. Internal help text, or a.

Page part that shouldn’t be pasted into a random shared doc just to.

Check if 15 px feels too tight.

How Font Size Pro helps you test text before publishing

Typography issues rarely come from a single setting alone. A paragraph mgiht be big enough but stil seem cramped. That’s because line height is too low.

A label can look clear by itself. Become hard to scan.

Letter spacing is too tight or the background color is close to the text color. Think about it.

Font Size Pro helps with those small choices. I mean, you paste or type your text into the Your text field, pick a.

Preset like Compact, Comfortable, Large, or Extra Large. Then adjust settings live.

The goal isnt to make every text block bigger. It’s to find the right size for different jobs. Dense dashboard labels, relaxed. Article copy, larger marketing text, or brief UI messages.

A good tester should always show the real words you plan to use.

Placeholder text hides issues like odd line breaks. Long button labels, short headings, or dense punctuation.

Testing font sizes with just clean sample sentences can miss the exact line that breaks your layout later.

Test live text size, spacing, and color contrast

The main controls focus on function, not decoration. Look, Size, in px, runs from 10 to 72 px.

Line height adjusts from 1.0 to 2.5. Letter spacing, in px, goes from minus 1 to 5 px.

These ranges cover most normal web text checks. From tiny helper text to large preview headings.

Used well, this tool is more than a simpel size previewer. It also works as a line height tester. When paragraphs feel tight.

It checks letter spacing too, helpful if a heading looks too squeezed or too loose. For body copy, watch out with negative letter spacing.

It might look neat on large headings but often makes longer text look squeezed.

Color is tested in the same workflow. And Pick text color. Background, adn watch the live WCAG contrast ratio and pass/fail results for AA or AAA update.

Here’s faster than picking type settings. On one screen and checking contrast somewhere else afterward.

How to preview pasted text with presets and sliders

Follow this order when you want clear results without wasting time. Start broad by choosing a preset, then make small tweaks.

If you adjust evry slider. At once, it becomes tough to see what actually improved the text. Seriously.

1. Open Font Size Pro live preview in your browser.
2. Paste or type your copy into the Your text box.
3. Select a built in Presets option like Compact, Comfortable, Large, or Extra Large.
4. Adjust Size (px) until the text fits its role on the page.
5. Change Line height between 1.0 and 2.5 until paragraphs feel spaced well.
6. Tweak Letter spacing (px) only once size and line height look right. Look, The slider works bewteen minus 1 and 5 px.
7. Pick Text color and Background with the color pickers. Fix any errors shown before you judge the preview.
8. Use Font to pick a font family. When Pro is availible. Or stick with the free default sans serif.
9. Click Sample text if you want quick preview text instead of your own.
10. Check the live WCAG contrast ratio and whether it passes AA or AAA guidelines.
11. Press Copy CSS to copy CSS. For font size, line height, letter spacing, color, and background.
12. Try Pro features like Compare, Read aloud, Pause, Stop, Save preset, CSV, JSON, PDF, Voice (Pro), Speed (Pro), and naming presets when available.

Teh paid Pro plan lets you handle up to 200,000 characters. It also unlocks Pro options like Compare, speech synthesis, saved presets and font choice.

You can export CSV, JSON, or PDF using the print dialog, too.

A practical order for changing typography settings

Font settings effect eachother. Like bigger text might need less letter spacing.

Also, smaller paragraphs could need more line height.

Even strong color contrast can tire the eyes. If line length is long. Lines sit too close together.

Start with the setting that affects readability most, then move to finer tweaks. Usually, that means size first. Then line height, letter spacing, and finally color contrast.

• Choose Compact for dense UI areas, then confirm labels remain easy to scan.
• Start with Comfortable as a solid option for normal paragraph text.
• Pick Large or Extra Large. Text needs to be read. From a distance or have more visual impact.
• Dont fix weak contrast by only increasing font size. But Change the colors instead.
• Avoid using wide letter spacing to save a poor font choice. It can cause new problems.

If you want to compare font sizes for a design choice, Pro’s compare. Mode shows three sizes side by side. The free version shows one preview. That is enough for adjusting a single setting.

Color and WCAG contrast text preview

Good readability depends on more than pixels.

Gray text on a pale background might look elegant in a design file. Cause issues on a real page. Font Size Pro shows WCAG contrast with ratio. AA or AAA status for your chosen Text color and Background.

Use that info as a guide, not a guarantee. The tool shows if a color pair passes contrast tests.

But it doesnt promise legal accessibility, context, text purpose, and page design matter too.

If you only want to check two colors quickly, try Color Contrast Quick.

If you’re still choosing your palette. Before adding text, Color Pal Lite helps you explore color choices first.

Use the CSS font size generator once the text looks right

The Copy CSS button is handy. Thats because it copies the settings you jsut judged in the preview.

The CSS it creates includes font size, line height, letter spacing, color, and background. Just like that.

That makes Font Size Pro a font size generator taht really works. You. See the text, then add those values straight into your stylesheet.

Copying too soon is a common mistake. A 16 px paragraph with 1.2 line height might seem fine. For a few words. But it often feels cramped in a full paragraph.

Try pasting a real sentence, a short heading, and a long heading. Also include one awkward label before copying the CSS.

If you work on front end code, treat the copied CSS as a. Base, then adjust it to fit your system. Your code might use tokens, rem units, inherited colors, or variables. That’s the point.

The tool gives clean CSS values. But it doesn’t have to match your whole codebase structure.

What you get for free and the Pro upgrade

The free version handles the basic reading setup. Paste text, preview it, tweak type. Colors, check contrast, and copy CSS. Realy.

Youll find Pro useful for bigger text. That saves your work, side by side.

Viewing, read aloud options, font family choice and exporting.

When you haven’t saved any presets, the area shows No saved presets yet. So The tool also has Get Embed Code and Embed.

Plus you can use Copy Code to paste the tool into a page.

Your privacy: localStorage and browser only use

Font Size Pro promises its 100% private.

Your data never leaves your device.

The app runs in your browser. This setup is perfect for quick typography checks. You can paste sensitive drafts without uploading text to a server.

Settings save in localStorage. That means your browser remembers them on your device. Meanwhile, you use the site.

If you clear site data or change browsers, those settings might disappear. So always copy any CSS you want to keep.

This privacy approach means the tool has no accounts. No cloud sync, collaboration, or server backup.

Think of it as a local space to preview text and CSS. Not a publishing sytem.

Common mistakes and fast fixes

• Only testing wiht perfect dummy text. Fix this by pasting your longest heading, shortest label and one dense paragraph from the real page.
• Changing letter spacing before font size. Fix it by picking font Size, px, then Line height. And finally Letter spacing, px.
• Using color pickers without checking warnings. Fix it by correcting values. If the app says Enter a valid color.
• Assuming bigger font is allways better. Fix it by seeing if bigger settings cause awkward line breaks or push content to far apart.
• Ignoring line height in paragraphs. Fix it by using the 1.0 to 2.5 Line height control to test spacing. Not just decoration.
• Copying CSS from a single short sentence. Fix it by previewing a real chunk of text before clicking Copy CSS.
• Thinking AA or AAA accessibility ratings mean full approval. But Fix it by usign contrast results for colors. Then review the page context separately.
• Expecting to upload custom fonts. Fix it by sticking with the default sans serif. For free or system fonts in Pro.

Frequently asked questions

What is a font size tester used for?

A font size tester lets you see how text looks in different sizes before publishing. With Font Size Pro, you can paste or type your text, then change.

The size, line height, letter spacing, text color, and background. When your happy with how it looks, you can copy the CSS. For use on your site.

Can I test line height and letter spacing?

Yes, you can.

This tool lets you adjust line height from 1.0 to 2.5. Letter spacing from minus 1 to 5 pixels. Well that means you can use it to test spacing. For paragraphs, headings, labels, or any interface text.

Does it check WCAG contrast?

Yes, it does. Font Size Pro shows a live WCAG contrast ratio. Tells you if it passes AA or AAA standards based on your text and background colors.

It helps you spot weak color combos. But shouldn’t replace official accessibility testing required by law.

Is my pasted text private?

The tool runs entirely in your browser. So yuor text doesn’t leave your device.

It uses localStorage to remember your settings. That makes it graet for private previews.

Wihtout sending anything to a server.

Can I copy usable CSS?

Yes.

After picking a readable style, just click Copy CSS. The copied code includes font size, line height, letter spacing, color, and background, everything you need.

Can I compare font sizes side by side?

Compare mode is part of the Pro version. And shows three sizes next to each ohter. The free version only has one preview at a time. That is fine when focusing on one setting.

Start by pasting real copy, choose comfortable settings. And adjust contrast before tuning spacing.

Copy your CSS only after the preview still reads well as a block.

If it feels tight here, it likely will feel worse. On a busy page.