SIM-only vs contract: what does each cost over 24 months?

Key takeaways

• SIM-only is usually the better value if you already have a phone you're happy with. You pay for calls, texts, and data only, so the monthly price is lower than a phone contract. Plans can run for 1 month, 12 months, or 24 months.
• A phone contract bundles a new phone with your plan and spreads the cost over a set term, commonly 24 months. It suits people who want a new phone and would rather not pay for it all at once.
• The fairest comparison is the total cost over the same period. Keeping your current phone and switching to SIM-only is the cheapest route. Buying a new phone outright and adding SIM-only can come out close to a contract, so check the totals.

 

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Your phone is paid off. Has your bill noticed?

It can happen. Some plans stay at the same price after the phone is paid off, unless you do something about it. Or you might be wondering whether your next phone needs a contract at all.

This guide compares SIM-only and contract plans side by side, shows what each can cost over two years, and helps you decide which one suits you.

What's the difference between SIM-only and a contract?

A SIM-only deal gives you calls, texts and data, and nothing else. The SIM (or eSIM) goes into a phone you already own, or one you've bought separately.

A phone contract, often called pay monthly, bundles the plan and a phone into one package. You pay a fixed monthly amount for both over a set term.

	SIM-only	Phone contract
What you get	Calls, texts and data for a phone you already have	A phone plus calls, texts and data in one package
Typical length	One month, 12 months or 24 months	Commonly 24 months, though 12 to 36 months all exist
Monthly cost	Lower, because no phone is being paid off	Higher, because the price of the phone is spread across the monthly bill
Upfront cost	Usually little or nothing, and the SIM is often free	Sometimes an upfront payment, depending on the phone and the deal
Credit check	Often not needed on rolling monthly plans, more common on 12 and 24 month deals	Usually needed, because the provider is lending you a phone
Leaving early	Easiest on rolling monthly plans	Can mean paying the remaining months or the rest of the phone's cost
Best for	Keeping your current phone, or buying one separately	Getting a new phone without paying for it all at once

Which is cheaper over two years?

Monthly prices tell only half the story. A fairer test is the total you'd pay over the same 24 months.

Here's a simple example. The numbers are illustrative to show the maths, so swap in your own.

Option	What you pay	Total over 24 months
Phone contract, new phone included	£40 a month for 24 months	£960
Buy the same phone outright, then SIM-only	£600 for the phone, plus £12 a month for 24 months	£888
Keep your current phone and go SIM-only	£12 a month for 24 months	£288

Notice where the real saving is. Buying a new phone outright and adding a SIM-only plan is only a little cheaper than the contract in this example. The big difference appears when you keep the phone you already have.

How to work out what your phone is costing you

1. Find your contract end date in your provider's app, online account or latest bill.
2. Ask your provider how much of your monthly price is for the phone and how much is for the plan.
3. Compare the plan part with a SIM-only price for the data you use.
4. If you want a new phone as well, add what it would cost to buy it outright.

What are the advantages of SIM-only?

• Lower monthly bills, because you're not paying off a phone.
• More choice on length. Rolling monthly plans let you change plan or leave without waiting for a term to end.
• You keep a phone you already like, or buy a new one when the price suits you.
• You can keep your number when you switch, using a PAC code.

What are the advantages of a phone contract?

• No big upfront payment for a new phone, because the cost is spread across the term.
• One fixed monthly payment covers the phone and the plan.
• You get a new phone sooner, if that matters to you.

Are SIM-only contracts worth it?

For most people who already own a phone, yes. SIM-only gives you the plan without paying for a phone you don't need. If you want a new phone and can't pay for it upfront, a contract is the easier route.

Choose SIM-only if

• You're happy with the phone you have.
• Your contract is ending, or has already ended.
• You'd like the option to change plan without waiting for a term to finish.

Choose a phone contract if

• You want a new phone and can't comfortably pay for it in one go.
• You like one fixed monthly payment that covers the phone and the plan.
• You're happy to commit for the full term.

Is it better to buy a phone outright?

If you can afford it, buying outright and adding SIM-only can be a little cheaper overall, as the example above shows. The catch is paying the full price at once. If that's too much, a contract spreads the cost out, and that's fine too.

Keeping your phone and changing the plan

If you're leaning towards SIM-only, here's where SMARTY fits. With SMARTY, plans roll monthly, so there's no minimum term to get stuck in. There's no credit check, and no annual price rises on monthly plans. Every plan includes a free SIM, or an eSIM if your phone supports it. You can bring your number with you. Have a look at our SIM-only plans.

FAQs

Is SIM-only better than a contract?

SIM-only is usually better than a contract for anyone who already owns a phone they're happy with, because the monthly price is lower and the plan can be as short as one month. A phone contract suits people who want a new phone without paying for it upfront.

Is it better to buy a phone outright and get SIM-only?

Buying a phone outright and adding a SIM-only plan is often a little cheaper overall than a phone contract. Buying outright means paying the full price upfront, so a phone contract may suit people who would rather spread the cost.

Can I switch from a phone contract to SIM-only?

Yes. You can switch from a phone contract to a SIM-only plan once the contract ends. A PAC code from your current provider lets you move your number to the new plan. Leaving before the end date may mean paying the remaining months' charges or the remaining cost of the phone.