Every business mobile renewal comes down to the same question: do we take new phones on contract, or keep what we have and pay less each month? The honest answer is that it depends on numbers you can work out in ten minutes, and most comparisons never show you the sum. Here is the maths, and the things that quietly change the answer.
The 30-second version
- A handset contract is a phone loan wrapped in a tariff. You pay for the phone either way.
- Work in totals over the full term, not in monthly prices.
- SIM-only wins when your phones have life left, which is most of the time.
- Handset contracts win when you need to refresh the fleet and want to spread the cost.
- Phones sold in the UK since December 2021 are unlocked, so moving to SIM-only is simpler than it used to be.
On this page
The sum itself
Compare like with like by working out the total cost of each option over the same period, then dividing by the number of months. Take one user as an example. The figures below are illustrative, not our prices, and the point is the method rather than the numbers.
| Handset contract | SIM-only, keep the phone | SIM-only, buy the phone | |
|---|---|---|---|
| Monthly tariff | Higher, phone included | Lower | Lower |
| Upfront | Usually nothing | Nothing | Cost of the handset |
| Over 24 months | 24 x tariff | 24 x tariff | 24 x tariff plus handset |
| You own the phone at the end | Usually yes | You already did | Yes |
| Flexibility | Tied for the term | Highest | High |
Do that for one user, multiply by the number of users, and the answer is usually obvious. Where it is close, the tiebreakers below decide it.
The things that usually decide it
- How old are the phones? If most of the fleet is one or two years old, paying again for handsets is money for nothing.
- Does everyone need the same phone? Field staff and desk staff rarely do, and SIM-only lets you mix.
- How often do you replace phones? Businesses that refresh on a fixed cycle often prefer the predictability of contracts.
- Do you want to own the devices? Owned handsets can be redeployed to new starters; contract handsets are tied to the line.
- Cash flow. Buying handsets outright is cheaper overall and heavier in month one.
- VAT. VAT-registered businesses can usually reclaim VAT on both, subject to HMRC rules on business use.
The trap to avoid
The expensive mistake is staying on a handset tariff after the phone is paid off. If your contract ended and nothing changed, you may be paying for a handset you already own. That is the first thing we look for on a bill.
Most fleets end up as a mix
In practice the sensible answer is rarely all one or the other. Give new handsets to the people whose phones are worn out or who genuinely need a better camera or battery, and put everyone else on SIM-only. Both sit on one account and one bill.
That also avoids the cliff edge where every phone in the business reaches end of contract in the same month.
What changes when you move to SIM-only
- Check the handsets are unlocked. Phones sold in the UK since December 2021 must be sold unlocked. Older ones may need unlocking first.
- Keep your numbers. Numbers move across with the switch, and nobody needs to tell customers anything.
- Decide the term. Shorter terms cost a little more per month and keep you flexible.
- Review the tariffs per user, rather than putting everyone on the same plan.
- Set spend caps so a single user cannot produce a surprise.
Want the sum done on your actual bill?
Send us a recent bill. We will work out both options over the full term for your users and tell you honestly which is cheaper, even if that means leaving things as they are.