Why Is My Mobile Conversion Rate So Low? 10 Checks for Online Stores

Open your analytics, split by device, and the pattern is often the same: phones bring most of the visitors, desktops bring a bigger share of the orders. Google's web.dev has a name for it, the mobile commerce gap: many sites get more traffic on mobile but more conversions on desktop. Part of that is shoppers who browse on the bus and buy at their desk. But web.dev is clear that poor mobile experience is part of it too, and that part is yours to fix.

The stakes are high. In Baymard Institute's 2026 mobile benchmark, mobile generates around three quarters of retail store visits, and 75% of the 150+ large mobile sites Baymard reviewed rated only "Mediocre" for mobile UX. Baymard adds that because these are big sites with big budgets, the problem is likely worse for smaller ones.

First, measure the gap properly

Before fixing anything, get two numbers: conversion rate on phones and on desktop, for the same period.

On Shopify, there's a Sessions by device report, and Shopify's behavior report docs suggest asking Sidekick to "Show my conversion rate by device type for the last 30 days." Filter out bot traffic first. Then open the Conversion rate breakdown report and compare the funnel by device: sessions with cart additions, sessions that reached checkout, and sessions that completed checkout. Where the phone funnel drops away from the desktop one tells you which of the checks below to start with:

• Phones add to cart far less often: start with checks 1-6 (speed, first screen, tapping, finding products).
• Phones add to cart but don't finish: start with checks 7-10 (forms, wallets, errors).

One caution for 2026: Shopify notes that a session measurement update rolled out from September 21 to 23, 2026, and session-based metrics may look different afterward. Compare periods on the same side of that date.

The 10 mobile checks

Speed and stability (checks 1-2)

1. Does the page load fast enough on a real phone? Google's Core Web Vitals set three targets: Largest Contentful Paint (loading) within 2.5 seconds, Interaction to Next Paint (responsiveness) of 200 milliseconds or less, and Cumulative Layout Shift (visual stability) of 0.1 or less. Google says to measure them at the 75th percentile of page loads, separately for mobile and desktop. Run your top landing pages through PageSpeed Insights and look at the mobile field data when it's available. Shopify stores also get web performance reports for all three metrics by page URL or page type, which shows whether product pages or collection pages are the slow ones.

2. Does the page jump while it loads? Layout shift is especially painful on a phone: an app banner or review widget loads late, the page moves, and the shopper taps the wrong thing. Load your product page on mobile data and watch the first few seconds. Anything that pops in and pushes content down is a candidate to reserve space for or remove.

The first screen and tapping (checks 3-4)

3. What does the first screen actually show? On a phone, the first screen is small. Check that a shopper can see what the product is, what it costs, and how to buy it without scrolling past an announcement bar, a cookie banner, a chat bubble and a popup. Each of those is reasonable alone. Stacked together on a small screen, they can cover the very thing the shopper came for. Our Shopify product page audit covers the first screen in detail.

4. Are buttons and links big enough to hit? Google's guidance on accessible tap targets recommends touch targets of around 48 by 48 device-independent pixels, about the size of a finger pad, with roughly 8 pixels between them. Check the places shoppers tap most: variant swatches, size buttons, quantity steppers, the cart icon, and filter options. A size button that's 30 pixels wide, sitting right next to the one beside it, causes wrong selections that shoppers then have to notice and undo.

Finding products (checks 5-6)

5. Can shoppers get to a broad list from the menu? On mobile, menus usually drill down one level at a time. Baymard found that 42% of mobile sites don't offer a "View All" option at each level of the catalog, so shoppers who want "all jackets" get stuck in narrow subcategories. Add a "View all" item at the top of each level of your menu.

6. Do search and filters work with a thumb? Two quick checks from the same Baymard benchmark: 27% of mobile sites don't put a visible search submit button next to the search field, and some shoppers never think to use the keyboard's search key. And when shoppers apply filters, show the applied filters above the product list, so they can see what's narrowing the results without reopening the filter panel. Then open your filter panel on a phone and check that it's easy to apply more than one option and get back to the results.

Forms and paying (checks 7-10)

7. Do your forms bring up the right keyboard and autofill? Google's payment and address form guide recommends using the right input types, such as type="email" and type="tel", so phones show the right keyboard, and using autocomplete values so browsers can fill in names, addresses and card details. This matters for any form you control: newsletter signups, back-in-stock alerts, a quote request, or a custom checkout if you're not on a hosted one. If you're on Shopify, the checkout itself is Shopify's, but your theme's forms are yours.

8. Are error messages specific? Baymard found that 93% of mobile sites don't use "adaptive" error messages, which explain exactly what's wrong (say, an email missing the "@") instead of a generic "invalid." On a phone, where the field with the error may be scrolled out of view, a vague message is a real roadblock. Submit each of your forms with a typo and see what happens.

9. Can buyers pay with a wallet? Typing a card number on a phone is the hardest part of checkout. On Shopify, accelerated checkout buttons let customers pay with Shop Pay, Apple Pay, Google Pay, PayPal and others using details already saved with that method. Which buttons appear depends on the methods you've activated and on the shopper's device and browser, so check your product page on both an iPhone and an Android phone.

10. Does the address step catch typos? Baymard reports that mobile users make address errors far more often because of autocorrect and small keyboards, and that 54% of mobile sites in its benchmark have no address validator or lookup. If your platform offers address suggestions at checkout, make sure they're on. If shipments are going astray, this is worth checking first.

Test it the way shoppers use it

Simulators help, but test on real phones too: one recent iPhone, one mid-range Android, on mobile data rather than office Wi-Fi. Go from an ad or search result to a product, add it to the cart, and get as far into checkout as you can. Write down every moment you wait, mis-tap, or have to look for something.

Then rank what you found by how many visitors it affects and how easy it is to fix. Make one change at a time, note the date, and compare the mobile funnel over equal periods before and after. If you don't have the traffic for an A/B test, our guide to CRO without A/B testing shows how to measure a change honestly.

The checklist (copy this)

• Conversion rate compared by device, bots filtered, same side of the September 21-23, 2026 Shopify session update
• Found where the phone funnel drops versus desktop
• LCP within 2.5 s, INP 200 ms or less, CLS 0.1 or less on mobile
• Nothing pushes the page around while it loads
• Product, price and buy button visible on the first phone screen
• Tap targets around 48 px, about 8 px apart
• "View all" at each menu level
• Visible search button; applied filters shown above results
• Forms use the right input types and autocomplete
• Error messages say exactly what's wrong
• Wallet payments checked on iPhone and Android
• Address suggestions or validation on, if your platform offers it
• Tested on real phones on mobile data; one change at a time

Where Cortality fits

A checklist tells you what to look at on a phone. It can't tell you which of these is costing your store the most.

Our free page leak scan renders your page at desktop and phone widths and predicts where visitors look, plus what fixing the leak could be worth. No install needed. It's a prediction from our attention model, not data from your real shoppers, so use it as a place to start.

Cortality's paid product measures how real visitors, on phones and desktops, use every part of your page, then gives you a ranked list of fixes with the exact change for each and re-measures after you ship a fix. See what a finding looks like and how it works.

Start your free week, and you see your first report before you pay. You save a card at signup, and nothing is charged until 3 days after your first report. Cancel before then and you pay nothing, and any charge can be refunded within 14 days. How the free week works.