Klaviyo Forms & Popups: How to Build High-Converting Signup Forms

Your email list is the engine of your retention marketing. And the signup form is the intake valve. Get it wrong, and you’re starving your entire email program of subscribers. Get it right, and you’re adding hundreds or thousands of qualified leads every month — automatically.

Most Shopify stores running Klaviyo have a basic popup: “Get 10% off. Enter your email.” It converts at 1.5-2.5%. That’s leaving 60-70% of potential signups on the table.

The top-performing stores we work with convert at 5-8% on their primary popup. Some hit 10%+ with targeted secondary forms. The difference isn’t magic — it’s strategic form design, smart targeting, and relentless testing.

Here’s how to build Klaviyo forms that actually perform.

Key Takeaways

The average Klaviyo popup converts at 2.3%. Top performers hit 5-8% with proper optimization
Multi-step forms (email first, then SMS, then preferences) collect 40% more data than single-step forms at comparable conversion rates
Exit-intent popups convert 2-3x better than time-delayed popups for desktop traffic
Mobile forms need a completely different approach — full-screen takeovers outperform bottom bars by 35%
A/B testing your headline alone can improve conversion by 20-40%
Targeting rules matter more than design — showing the right form to the right visitor is half the battle

Before we get into Klaviyo-specific setup, let’s break down what makes a popup convert.

Headline: Your One Shot

You have 2-3 seconds before someone closes your popup. The headline must communicate value instantly.

Weak: “Join our newsletter” Better: “Get 10% off your first order” Best: “Your first order ships free — enter your email”

The best headlines combine a specific benefit with low friction. “Join our newsletter” communicates zero value. “10% off” is clear but generic. “Free shipping” is specific and addresses the #1 reason for cart abandonment.

Test these headline formulas:

Discount-led: “Take 15% off your first order”
Shipping-led: “Unlock free shipping on your first purchase”
Exclusivity-led: “Get early access to new drops + member-only pricing”
Content-led: “Get our [product category] style guide — free”

The Offer: What Are You Trading For?

The offer must match the value of what you’re asking for.

What You’re Asking	Minimum Offer
Email only	10% off or free shipping
Email + SMS	15% off or free shipping + gift
Email + SMS + preferences	20% off or exclusive bundle

Asking for more data? Increase the incentive. We see stores ask for email, phone number, birthday, and product preferences with a 10% offer — and then wonder why their conversion rate is 0.8%.

Design: Less Is More

One clear CTA button. Not two. Not three.
Minimal form fields. Email only on step 1. Always.
High contrast between the popup and background. The popup should visually pop (hence the name).
Mobile-optimized. If your popup isn’t designed for mobile first, you’re ignoring 65%+ of your traffic.
Brand-consistent. Match your site’s typography, colors, and imagery. Generic popups feel spammy.

Setting Up Forms in Klaviyo

Step 1: Choose Your Form Type

Klaviyo offers several form types. Here’s when to use each:

Best for: Primary list-building on desktop and mobile
When: First-time visitors, time-delayed or exit-intent trigger
Average conversion: 3-5% when optimized

Best for: Less intrusive secondary offers
When: Returning visitors, specific product pages
Average conversion: 1.5-3%

Embedded Form:

Best for: Footer signup, blog sidebar, dedicated landing pages
When: Always visible — no trigger needed
Average conversion: 0.5-1.5% (lower intent but always-on)

Full-Screen Takeover:

Best for: Mobile traffic, aggressive list-building campaigns, BFCM
When: High-intent moments like exit or after scroll
Average conversion: 4-7% on mobile

For most stores, start with a popup for desktop and a full-screen form for mobile. Run them simultaneously with device-targeting rules.

Step 2: Build Multi-Step Forms

Single-step forms that ask for email, phone, and preferences all at once convert poorly. Multi-step forms break the commitment into digestible pieces.

In Klaviyo’s form builder, you can add up to 5 steps. Here’s the optimal structure:

Step 1: Email Capture

Headline + offer
Single email field
Submit button
This is the only required step — even if someone drops off after this, you have their email

Step 2: SMS Opt-in (Optional)

“Want your discount code via text? Add your phone number”
Phone number field with SMS consent checkbox
Skip option clearly visible
Adds 30-40% SMS opt-in rate on top of email capture

Step 3: Preference Collection (Optional)

“Help us personalize your experience”
2-3 buttons for product category preferences or quiz-style questions
This data feeds directly into Klaviyo profile properties for segmentation
Skip option available

Step 4: Thank You + Coupon Delivery

Display the coupon code directly (don’t make people check their email)
“Your code: WELCOME15” in large text
CTA button: “Start Shopping” that links to bestsellers or a curated collection

This multi-step approach typically converts at 4-6% on email capture (step 1), with 35-45% of those also opting into SMS (step 2), and 50-60% providing preferences (step 3).

Step 3: Configure Targeting Rules

This is where most stores fail. Showing the same popup to every visitor is a waste. Klaviyo’s targeting options let you get surgical.

First-Time Visitors:

Show your primary discount popup
Trigger: 5-8 seconds on site OR 50% scroll OR exit intent (desktop)
Frequency: Show once. If dismissed, don’t show again for 30 days.

Returning Visitors (No Purchase):

Show a different popup with a stronger offer or different angle
Trigger: 3-5 seconds (they already know your brand)
Consider: “Still thinking about it? Here’s free shipping on us”

Returning Visitors (Previous Purchase):

Don’t show a discount popup — they already buy from you
Instead: SMS opt-in, loyalty program signup, or new product alert
Or suppress the popup entirely and let them shop

By Traffic Source:

UTM-based targeting in Klaviyo lets you match the popup to the ad
Visitor from a Facebook ad about a specific product? Show a popup with that product + discount
Visitor from organic search? They’re researching — offer a guide or content piece

By Page:

Product pages: Show product-specific popups or “Notify me when on sale”
Collection pages: Show category-level offers
Blog pages: Content upgrade or guide download
Cart page: Do NOT show a popup here. You’ll cause abandonment.

Step 4: Set Up Display Timing

Timing affects conversion rates more than most people realize.

Time-Delay Triggers:

Desktop: 5-8 seconds is the sweet spot. Under 3 seconds feels aggressive. Over 15 seconds and you’ve already lost the casual browsers.
Mobile: 8-12 seconds. Mobile users are touchier about interruptions.

Scroll-Based Triggers:

30-50% scroll depth works well for content pages
Shows the popup after the visitor has demonstrated some engagement

Exit-Intent (Desktop Only):

Fires when the mouse moves toward the browser’s close button or address bar
Converts 2-3x better than time-delay because it catches people on their way out
The “last chance” framing is psychologically powerful

Mobile Exit-Intent Alternative:

True exit-intent doesn’t work on mobile (no mouse cursor)
Use back-button intent or aggressive scroll-up detection instead
Klaviyo handles this with their “exit intent” option on mobile, which triggers on scroll-up behavior

A/B Testing Your Forms

Klaviyo has built-in A/B testing for forms. Use it. The stores that test consistently outperform those running on assumptions.

What to Test (In Priority Order)

Headline / Offer — Highest impact. Test 10% off vs. free shipping vs. dollar-amount off. We’ve seen free shipping beat 10% off by 30% for stores with AOVs above $60.
Form Type — Test popup vs. flyout vs. full-screen on the same audience. Let the data decide.
Timing — Test 5-second delay vs. exit-intent vs. 30% scroll. Run each variant for at least 1,000 impressions before drawing conclusions.
Number of Steps — Test single-step (email only) vs. multi-step (email + SMS). The multi-step version collects more data, but does it reduce overall email signups?
Design — Test image vs. no image, button color, form placement. These typically have smaller impact than the above, but marginal gains add up.

How to Run a Valid Test

Run each variant for at least 7 days to account for day-of-week variation
Minimum 1,000 impressions per variant before evaluating
Test one variable at a time. Changing the headline AND the offer AND the design simultaneously tells you nothing.
Use Klaviyo’s built-in traffic split (50/50 is standard)
Check both conversion rate AND downstream revenue — a form with a lower conversion rate but higher-quality subscribers might generate more revenue

Advanced Form Strategies

Gamified Popups (Spin-to-Win)

Spin-to-win popups are controversial. They convert at 7-12% — dramatically higher than standard popups. But the subscriber quality is often lower because people are motivated by the game, not your brand.

Our take: Use them for BFCM and major sale events when you want maximum list growth. Avoid them as your everyday popup. The marginal subscribers you gain rarely justify the discount margin erosion year-round.

Klaviyo doesn’t have a native spin-to-win, but integrations like Privy or Justuno can feed into Klaviyo lists. Alternatively, use Klaviyo’s multi-step form with a “mystery discount” reveal on step 2 — it creates similar curiosity without the gimmick.

Back-in-Stock and Price Drop Forms

These aren’t traditional signup forms, but they’re powerful list builders. On product pages where items are out of stock, embed a Klaviyo form that says:

“Notify me when this is back in stock — enter your email”

These convert at 8-15% because the intent is extremely high. The visitor already wants the product. Tag these subscribers with the specific product they want, and trigger a back-in-stock flow when inventory is replenished.

Quiz Funnels as Forms

Replace your popup entirely with an on-site quiz. “Find your perfect [product]” quizzes serve dual purposes:

They collect email (to deliver results)
They collect rich preference data (quiz answers become Klaviyo properties)
They provide a personalized product recommendation (higher conversion)

Quiz funnels typically convert at 10-20% of quiz starters into email subscribers. The data quality is exceptional because every answer maps to a preference you can use in segmentation.

Tools like Octane AI or Typeform integrate with Klaviyo to pass quiz data directly into profile properties.

Form Performance Benchmarks

Here’s what to target based on the stores we manage:

Metric	Below Average	Average	Good	Excellent
Popup conversion rate	< 2%	2-3%	3-5%	5%+
Mobile form conversion	< 1.5%	1.5-2.5%	2.5-4%	4%+
SMS opt-in (step 2)	< 20%	20-30%	30-45%	45%+
Exit-intent conversion	< 3%	3-5%	5-8%	8%+
Email list growth rate	< 5%/mo	5-8%/mo	8-12%/mo	12%+/mo

If your primary popup converts below 2%, something is fundamentally wrong — either the offer, the timing, or the targeting. Start by testing a stronger offer and exit-intent timing.

Common Mistakes

Showing popups to existing subscribers. Use Klaviyo’s “Is not in list” targeting rule to suppress forms for anyone already on your list. Showing a signup popup to someone who already signed up is a bad experience.
Identical mobile and desktop forms. Mobile needs different timing, different form types (full-screen works better), and larger tap targets. Build separate forms.
No suppression after dismissal. If someone closes your popup, don’t show it again in 5 minutes. Set a 14-30 day suppression period. Klaviyo’s “Don’t show again for X days after close” setting handles this.
Asking for too much in step 1. Email only. That’s it. Collect everything else in subsequent steps.
Not delivering the incentive immediately. Show the coupon code on the thank-you step AND send it via email. Making people hunt through their inbox for a discount code creates friction at the worst possible moment.
Ignoring form analytics. Klaviyo shows you impressions, submissions, conversion rate, and even step-by-step dropoff for multi-step forms. Review these weekly. A form that converted at 5% three months ago might be at 2% today due to audience fatigue.

The Bottom Line

Your Klaviyo forms are the gateway to your entire email and SMS program. A 1% improvement in popup conversion rate can mean thousands of additional subscribers per month — and tens of thousands in additional revenue downstream.

Build multi-step forms. Target them precisely. Test everything. And remember: the best popup is the one that feels like a genuine value exchange, not an interruption.

Want us to set this up for your store? Get a Free Audit