Square vs SumUp vs Zettle: Best Card Reader for a UK Small Business

For most UK small businesses, SumUp is the cheapest entry point with no monthly fees and the lowest hardware cost, Square is the most powerful all-rounder with the strongest software ecosystem, and Zettle (PayPal) sits in between with deep PayPal integration. As a rough rule: SumUp for sole traders and market traders, Square for shops and growing businesses, Zettle if you already use PayPal heavily.

Square vs SumUp vs Zettle at a glance

Why does this comparison matter?

These three are the main "no monthly fee" card readers for UK small businesses. They all charge a small per-transaction fee instead of a fixed monthly subscription, which makes them ideal for businesses that take fewer than 1,000 card payments a month.

The differences come down to:

• Hardware — what the actual card reader looks and feels like
• Per-transaction fees — small but compound over time
• Software — what the surrounding apps and features look like
• Ecosystem — what else integrates with each

SumUp — the cheapest entry point

SumUp is the simplest, cheapest, and most beginner-friendly option. It is designed for sole traders, market traders, and mobile sellers who just need to take card payments occasionally.

What you get:

• £19 for the entry-level Air reader (the smallest, cheapest card reader on the UK market)
• 1.69% per transaction (lowest of the three for in-person payments)
• Free SumUp app for managing transactions
• Basic invoicing and a free online store ("Online Store" — limited but functional)
• No monthly fee, no contract, no minimum volume

Best for:

• Market stalls and pop-ups
• Mobile service businesses (mobile hairdressers, dog walkers, gardeners)
• Sole traders taking occasional payments
• Anyone who wants the absolute simplest setup

Limitations:

• Software is basic compared to Square
• Online store is functional but not as polished as Shopify or even Square Online
• No serious inventory management
• Customer support is fine but not exceptional

Square — the most powerful all-rounder

Square is the most feature-complete option. It started as a card reader and grew into a full small business platform — point of sale, online store, appointments, invoices, payroll (US only), and more.

What you get:

• £19 for the entry-level Square Reader
• 1.75% per transaction in person, 1.4% + 25p online
• Full Square Point of Sale app (free)
• Square Online (free e-commerce store)
• Square Appointments (free booking system, otherwise £20+/month)
• Strong inventory management
• Integrations with hundreds of other tools

Best for:

• Retail shops with physical premises
• Restaurants and cafés
• Service businesses with multiple staff (hairdressers, salons, fitness studios)
• Businesses that want to consolidate POS, online store, and bookings into one platform
• Anyone planning to scale beyond £100k turnover

Limitations:

• Slightly more expensive per transaction than SumUp (small difference)
• More features than most small businesses actually use
• Hardware feels slightly more premium-priced for higher-tier readers (£169 for the Square Terminal)

For most growing small businesses, Square is the right call. The free Square Appointments and Square Online features alone are worth a few hundred pounds a year compared to paying for separate booking and e-commerce tools.

Zettle by PayPal — the PayPal play

Zettle was an independent Swedish company that PayPal bought a few years ago. Today, it is essentially "PayPal's card reader and POS product".

What you get:

• £29 for the entry-level Zettle Reader 2
• 1.75% per transaction in person
• Online payments via PayPal at 1.2% + 5p (significantly lower than competitors for online sales)
• Decent POS app with basic inventory
• Direct PayPal integration — money lands in your PayPal account

Best for:

• Businesses that already use PayPal heavily
• Sellers who do a lot of online sales via PayPal and want one consolidated dashboard
• Businesses dealing with international customers (PayPal is widely recognised globally)

Limitations:

• Hardware is slightly more expensive than the other two
• POS software is less full-featured than Square's
• Tied to PayPal — if you do not want to use PayPal for online sales, the main advantage disappears
• Zettle has been progressively de-prioritised by PayPal in some markets, raising long-term uncertainty

For most UK small businesses, Zettle is the right call only if PayPal is already a core part of how you take payments online.

What does each cost in real life?

Let us run the numbers on a small business taking 200 card payments a month, average value £20.

Monthly card volume: 200 × £20 = £4,000

Fees per provider:

• SumUp (1.69%): £4,000 × 1.69% = £67.60/month
• Square (1.75%): £4,000 × 1.75% = £70.00/month
• Zettle (1.75%): £4,000 × 1.75% = £70.00/month

The fee differences are small. Over a year, SumUp saves you about £30 vs Square or Zettle at this volume. That is a rounding error compared to the value of the surrounding software features.

The real question is not "which has the lowest fee" but "which has the right software for my business".

What does SME Shack recommend?

For most UK small businesses we work with:

• Sole traders, market traders, mobile sellers → SumUp
• Shops, restaurants, service businesses with growth ambitions → Square
• PayPal-heavy online sellers → Zettle

If you are also setting up an online store, we usually recommend Shopify (a separate platform) for the e-commerce side and one of these three for in-person payments. Shopify Payments (Shopify's own card reader) is also worth considering if your business is e-commerce-led and in-person payments are secondary.

See our services page for what we offer in the e-commerce build space.

Frequently asked questions

Q: Are there any monthly fees I should watch out for?

A: All three providers have free entry-level plans. Square and Zettle both offer paid tiers with extra features (Square Appointments Plus, Zettle Pro). For most small businesses, the free tiers are enough.

Q: How quickly does the money arrive in my bank account?

A: SumUp and Square typically pay out within 1–3 working days. Zettle is similar but goes via PayPal first if you have it linked. For faster payouts, all three offer "instant payout" features for an additional small fee.

Q: Can I take contactless and chip-and-pin with the entry-level readers?

A: Yes. The £19 SumUp Air, £19 Square Reader, and £29 Zettle Reader 2 all support contactless, chip-and-PIN, Apple Pay, and Google Pay out of the box. You do not need to pay for a more expensive reader to get these features.

Q: Do I need a separate till system, or is the card reader enough?

A: For most small businesses, the free POS app on your phone or tablet is enough. If you want a dedicated till that prints receipts, all three providers sell hardware bundles (£100–£300). Whether to upgrade is purely a question of how busy your shop is.

Q: What about other options like iZettle, Tide Card Reader, or Stripe Terminal?

A: iZettle is the old name for Zettle — same product. Tide's card reader is similar to SumUp and works fine if you bank with Tide. Stripe Terminal is excellent but aimed at developers and businesses that want to integrate payments into custom software — overkill for most retail businesses.

Q: Can I switch from one to another later?

A: Yes. You can cancel any of these any time, return the reader if you want, and switch to a different provider. No long contracts, no exit fees.