The painful truth is that it really doesn’t matter how hard you worked on your paid ads, SEO, marketing campaign, and sales strategy if your forms don’t load FAST. Heavy forms with oversized images and clunky code will slow your site to a crawl, and people will get frustrated and drop off.

The most common reason forms get heavy and load slowly is heavy design elements to make the form look good. However, you can’t prioritize building a beautiful and engaging form over speed; you need lightning-fast forms so visitors stay engaged from the very first second.

Let’s get into how to embed a form on your website without compromising speed.

Why Website Speed Matters (And How Forms Can Affect It)

The recommended loading speed is 2 seconds or less; anything longer and you will lose website visitors before they see your form, killing your chances for lead generation and conversions. Most Google searches come from mobile users, and 53% of them will ditch your page if the website loading speed is slower than 3 seconds. If your SEO and marketing strategy is working well enough to get people to your page, but your website speed is too low, search engines will lower your rankings, and all your efforts will be wasted

Why Heavy Forms Slow Down Your Website

If your forms include

• Third-party tracking scripts
• Social/facial logins
• Unoptimized embeds (like iframes loading 50KB of junk)
• Excessive code to customize the form

They are very likely to lag because each of the elements above adds latency, bloating load times to over 3 seconds or higher. This leads to too many interactive fields with poor optimization that will drive users away before they even get to see your product value. For example, Akamai found that just a 100ms delay reduced conversions by 7%, while Yelp saw a 15% conversion boost after optimizing its FCP.

How to Embed a Form Without Slowing Down Your Website

Here’s how to reduce your loading speed without compromising on beautiful form design:

1. Choose a Lightweight, Performance-Focused Form Builder

Building forms from scratch can easily lead to bulky scripts, slowing you down with over 100KB of JavaScript if not carefully optimized. Using a form creator tool like Formplus that prioritizes performance gives you:

• Pre-optimized templates (loads 2X faster than the industry average)
• Automatic code minification
• Built-in asynchronous loading

2. Use Asynchronous Loading

By default, browsers pause page rendering to load scripts, including form code. So, if your form script is heavy, your website will load slowly as it first tries to load the form code before fully displaying your webpage.

However, asynchronous loading allows you to load parts of a webpage in the background without slowing down everything else you see and interact with, removing the frustrating delay. This is how it works: 

• async: Lets scripts load in the background (use for non-critical features like analytics).
• defer: Waits to run scripts until after the page loads (perfect for forms to ensure they work correctly).

Pro Tip: Combining asynchronous loading with lazy loading (check 5) can help reduce your loading speed by over 50%

3. iFrame vs. JavaScript – Which One is Better?

Both IFrames and JavaScript have tradeoffs for embedding forms. IFrames offer isolation (great for contact forms) but can introduce their own loading overhead. JavaScript embeds can provide more flexibility (required for multistep surveys) and better integration, but require careful optimization to avoid performance issues.

If you are manually managing different embed methods (iframe vs. JavaScript) for multiple forms, it becomes complex. You have to constantly switch between iframe and JavaScript every time you want to embed different elements, it’s simply not sustainable.  However, if you are using a smart form-building software, it automatically chooses the fastest embed method, saving you the hassle.

4. Optimize Form Assets

Your form should always follow the 3-second rule, it’s even better if it’s 2 seconds or less. Using fast-loading form assets can help you reduce loading speed. This includes

• Minifying your CSS/JS using a tool like UglifyJS cuts file sizes by up to 40%
• Compress images to less than 1MB 
• Purge unused libraries (e.g., ditch jQuery if not needed).

5. Implement Lazy Loading for Forms

Another way to ensure your form doesn’t reduce your website speed is to enable lazy loading so that the form only loads when a visitor is near it. This means the browser doesn’t need to download and render your form until the user scrolls near it.

 This way, the form loads separately from your webpage as a whole and has no chance of delaying your loading speed.  You can do this by adding an HTML code snippet: 

6. Reduce Third-Party Dependencies

Third-party elements like reCAPTCHA can introduce latency to page loading speed. Now imagine having multiple third-party elements on your page; the cumulation of these will slow down your form and frustrate visitors, increasing your bounce rate.

You can either stick with one third-party element per page or use alternatives like use laterntive options like Formplus with invisible CAPTCHA  that saves you the hassle of 300ms Google reCAPTCHA. The form also has native analytics, eliminating the need for 3rd-party tracking scripts.

7. Enable Caching & CDN for Form Assets

Without caching, every new visitor downloads your form’s scripts and styles from scratch—even if they’ve seen your site before. However, when you enable caching, your website stores form assets locally after the first visit, making subsequent loads nearly instant.

Also, using CDNs ensures your website isn’t overburdened by serving visitors from servers closer to them. For example, a visitor in Paris gets forms from a European server, not the US. This will not only reduce your load time, but it also decreases your hosting costs as it helps you use less bandwidth.

Bonus Tips for Faster Form Performance

• Keep fields minimal – less is more: Making your form engaging doesn’t necessarily mean you have to embed every interactive element.  So, only include questions and fields you need (27% of people will ditch a form and never look back if it’s too long).
• Optimize mobile form performance: ensure your forms are mobile responsive (the majority of search comes from mobile). This means your form should automatically adjust to mobile screen size, form assets should display correctly on mobile, and multi-page forms for long forms to reduce scrolling on mobile.
• Regularly test form speed: Use tools like Google PageSpeed Insights to measure your website’s speed and identify areas for improvement. They help you analyze page load time and provide suggestions for optimization, including image optimization, minimizing render-blocking resources, and enabling browser caching.

Our Bottom Line

A beautiful form means nothing if it doesn’t load fast. If visitors don’t get what they need instantly, they’re gone. So, every second of delay costs you leads and revenue. You have to ensure your forms look good and provide a great user experience with a fast loading time.

Ready to build forms that convert? Get started with Formplus!