Eighty percent of your traffic is on mobile. Forty percent of your revenue is. If those numbers feel familiar, you have a mobile conversion problem. Here’s what causes it — in roughly the order we find them when we audit.
1. Hero is too tall
Mobile heroes routinely take 110% of viewport height. The customer scrolls past nothing but a logo and a hero image before they see anything to buy.
Fix: keep the hero under 80% viewport on mobile. Show product or category preview above the fold. The fold still matters — it just isn’t where it used to be.
2. Sticky add-to-cart is missing
On desktop, the add-to-cart button is in view ~70% of the time on the PDP. On mobile, it’s visible for maybe 8 seconds out of a 90-second session — the rest of the time the customer is scrolling reviews, descriptions, related products.
Fix: sticky bottom add-to-cart bar on mobile PDPs. Show the price, variant selector or current selection, and an Add button. This single change is worth 5–15% PDP-to-cart on most stores.
3. Variant pickers are tap targets too small
Default Dawn variant pills on mobile are often 32–36px tall. Apple’s HIG says 44px minimum. Customers fat-finger the wrong size, churn out of frustration.
Fix: 44px minimum for any tappable element. Yes, that means resizing your variant pills.
4. Forms ask for too much
A mobile checkout that asks for “Address line 2” as a required field will lose customers. So will any form that auto-focuses one field after another (jumping the keyboard around the page).
Fix: mark non-essential fields optional. Use proper autocomplete attributes (given-name, family-name, street-address, postal-code) so the browser autofills correctly. Test the form on a real iPhone, not a desktop emulator.
5. Images are too heavy
A 4MB hero image on mobile is fine on Wi-Fi and a disaster on 4G. LCP > 4 seconds is hurting your conversion before the customer even sees the page.
Fix: WebP with srcset so mobile gets a smaller variant. Aim for < 200KB on the hero. Lazy load anything below the fold, eager load anything above.
6. Pop-ups are punishing
Mobile pop-ups that take 80% of the screen, can’t be dismissed without precision, and re-trigger every visit are a special kind of self-harm.
Fix: delay first-time pop-ups by at least 15 seconds or one scroll event. Make the close target unmistakable. Don’t show the same pop-up twice in 30 days.
7. Cart drawer is broken on mobile
A common Dawn issue: the cart drawer takes the full screen, but the close button is way at the top, and the customer can’t see it without scrolling. They tap “Back” — leaves the store entirely.
Fix: sticky close button, sticky checkout button, both visible without scrolling. Test the drawer on an iPhone SE — if it works there, it’ll work everywhere.
Diagnose, don’t guess
Before fixing anything, look at the data:
- Filter Shopify’s analytics or GA4 to mobile only.
- Compare conversion rate by step — landing → PDP → cart → checkout → purchase.
- Find the biggest drop-off vs. desktop.
- Fix that step first.
Most of the time the biggest drop is PDP-to-cart, and the fix is the sticky add-to-cart bar plus larger tap targets. The rest matters; that’s where to start.