SumUp vs Zettle vs Square vs Aphelios: UK Mobile POS Compared 2026

Written by Calvin Lo, Founder of Aphelios Software | July 2026 | 9 min read

If you run a small business in the UK: a market stall, shop, café or pop-up: you have almost certainly compared SumUp, Zettle and Square. They are the three biggest names in mobile card payments, and all three let you accept card payments from a phone.

But here is the question most comparison guides skip: do you need a card reader at all, and do you need more than payments? In this guide we compare SumUp vs Zettle vs Square head-to-head, and explain when an all-in-one platform like Aphelios is the better choice for UK businesses that also run stock, suppliers and customers.

The Quick Answer

SumUp UK: The Low-Cost Card Reader

SumUp is the most popular card reader in the UK, and for good reason: the hardware is affordable, the app is simple and there is no monthly fee for basic payments. At 1.69% per transaction, SumUp is also the cheapest standard rate of the three card reader brands.

What SumUp Does Well

• Lowest standard transaction fee of the three (1.69%)
• Card readers from around £29, no monthly subscription needed
• Simple, reliable tap-and-go payments on the go
• Free invoicing, loyalty and QR code order features

Where SumUp Falls Short

• Inventory is a product list with stock levels: no multi-location sync, no barcode workflows
• No purchase orders, supplier management or CRM
• No AI features: stock checks, invoice scanning and reporting are all manual
• You still need to buy a reader for in-person payments

Zettle UK: PayPal's Card Reader

Zettle, owned by PayPal, is SumUp's closest rival. The reader lineup is similar, the app is polished and PayPal merchants get a seamless link to their existing PayPal accounts. The standard transaction rate is 1.75%.

Zettle's inventory features are basic: you can track stock levels and manage a product library, but there is no purchase order workflow, no supplier management and no multi-location stock sync. Zettle added some CRM-lite customer features, but it remains a payment-first tool.

Square UK: The Ecosystem Player

Square offers more than a card reader: a free POS app, an online store, appointments and invoices. It is the most feature-rich of the three reader brands, and its 1.75% transaction fee is competitive.

But advanced inventory features, multi-location support and deeper reporting sit behind paid add-ons, and there is no native CRM, purchase order system or AI assistant. Square's data is also hosted outside the UK, which matters to GDPR-conscious business owners.

Aphelios: The No-Hardware Alternative

Aphelios takes a different approach. Instead of selling you a card machine, it turns any phone, tablet or computer into a checkout and processes payments through Stripe: 1.5% + 20p per transaction, with cards, Apple Pay, Google Pay and printable QR codes.

The bigger difference is what sits around payments. Aphelios is an all-in-one platform: full inventory management with real-time multi-location sync, purchase orders and supplier management, an integrated CRM, invoicing, barcode scanning and an AI Business Assistant that answers stock questions, scans supplier invoices and creates purchase orders automatically.

Pricing starts at £29.99/month for up to 2 users with every feature included: no feature gating, no paid add-ons. Data is UK-hosted on Microsoft Azure and GDPR compliant.

When to Choose Each Option

Choose SumUp, Zettle or Square if:

• You only need to take in-person card payments a few times a week
• You manage stock in a spreadsheet or not at all
• You do not want a monthly software subscription

Choose Aphelios if:

• You sell physical products and need real inventory control
• You run more than one location: shops, stalls, markets or pop-ups
• You want purchase orders, CRM, invoicing and AI in one platform
• You prefer no hardware, no card reader to buy or replace

Many UK business owners start with a card reader and outgrow it within a year: the moment stock errors, missing purchase orders or disconnected systems start costing time and money. When that happens, switching to an all-in-one platform like Aphelios removes the whole jumble of separate tools.

Try Aphelios free for 14 days with no credit card required, and see whether your business is ready to move beyond the card reader. And if you are comparing prices first, read our full breakdown of card machine fees in the UK for 2026.