Bluetooth or 4G Card Machine: Which to Choose
Bluetooth card machines (SumUp Air, Zettle Reader) pair with a smartphone via Bluetooth and use the phone signal. They cost less (£29 to £79) but depend on the phone battery and signal. 4G card machines (SumUp Solo, Zettle Terminal, Square Terminal, Dojo Go) are standalone with their own SIM. They cost more (£99 to £150 outright or £40 monthly rental) but remove the phone dependency. Choose Bluetooth for occasional sub-£2,000 monthly trade, 4G for daily trading or any mobile use.
What this means for your business
Bluetooth card readers are the entry-level option. They are small (palm-sized), light, and cheap (£29 to £79 outright). They pair via Bluetooth with a smartphone or tablet running the provider app, and use the phone's data connection to process transactions. The card reader itself has no SIM, no display in some cases (SumUp Air has a basic LED indicator), and no battery beyond what the small unit needs for its own NFC and chip-reader functions.
4G card machines are standalone. SumUp Solo, Zettle Terminal, Square Terminal and Dojo Go each have a 4G SIM, a colour touchscreen, their own battery (8 to 12 hours), and connect directly to the mobile network without a phone in the loop. They cost more outright (£99 to £150) or monthly (£40 on Dojo Go). The advantage is reliability and independence from phone state, the disadvantage is the higher upfront cost and slightly larger device size.
Decision matrix. Occasional trade (craft fairs, weekends, sub-£2,000 monthly volume), no daily use, willing to manage phone battery: Bluetooth wins on cost. Daily trade, mobile rounds, can't rely on phone state, customer wants quick service: 4G wins on reliability. Mid-range case (regular weekly trade at £2,000 to £5,000 monthly volume): 4G is the safer default because the reliability difference shows up at scale and the cost difference (one-time £70 to £100) is amortised in months.
Key points
- Bluetooth readers (SumUp Air, Zettle Reader) pair with a smartphone and cost £29 to £79
- 4G machines (SumUp Solo, Zettle Terminal, Square Terminal, Dojo Go) are standalone and cost £99 to £150
- Bluetooth depends on phone battery and signal, 4G is independent
- Bluetooth wins for occasional sub-£2,000 monthly trade
- 4G wins for daily trade, mobile rounds, or where customer service speed matters
- Mid-range case: 4G is the safer default because reliability scales
- Both support Apple Pay, Google Pay, chip-and-PIN and contactless cards
Common pitfalls
- Choosing Bluetooth on price for a daily mobile trade, the phone-battery dependency causes lost transactions
- Forgetting that Bluetooth pairing breaks in crowded venues with signal interference
- Buying a 4G device for occasional craft fair use, the higher cost is not recovered on low volume
- Not testing the Bluetooth range, some devices need the phone within 1 metre to maintain pairing
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Open quote form →Related questions
Can I use a Bluetooth reader with a tablet instead of a phone?
Yes. SumUp, Zettle and Square all have apps for iOS and Android tablets. Tablet-based setups are common in cafes and counter-service venues where the tablet stays at the counter and the Bluetooth reader hands to the customer for tap or PIN entry.
How long does a Bluetooth pairing take?
First pairing takes 1 to 2 minutes via the app. Subsequent pairings are automatic when the reader and phone are both on and within range. If the reader has been off for several hours, the first transaction of the day may need a manual pairing refresh.
Director, MerchantHQ
Oliver leads MerchantHQ's editorial and comparison research. With a background in UK commercial finance, he oversees provider analysis, rate verification, and industry reporting across all verticals.
Last reviewed: 18 May 2026