Total cost comparison of SIM-only plus owned phone vs mobile contract.

SIM-only plus buying phone outright is almost always cheaper than a mobile contract over the contract period. Contract 40/month × 24 months = 960. SIM-only 15/month × 24 = 360, plus 600 phone = 960. Identical in this example. But SIM-only commonly 10-15/month for equivalent data, making it 240-360 total — dramatic saving.

Contracts appeal because they split the device cost into monthly payments and feel 'free'. The math rarely supports them for anyone who could buy outright or finance cheaper. Exceptions: very specific premium phones on exclusive deals, or customers who genuinely couldn't afford lump sum.

How to use it

Input SIM-only monthly cost, phone purchase price (outright), contract monthly cost, and contract length in months. The tool shows total cost of each option.

What the result means

SIM-only total is monthly × contract length + phone price. Contract total is monthly × length. Winner is lower total. SIM-only saving shows the explicit saving from the cheaper route.

Quick example

With sim-only monthly of 15 and phone purchase price of 700 (plus contract monthly of 40 and contract length of 24), the result is Contract. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter SIM-Only Monthly, Phone Purchase Price, Contract Monthly, and Contract Length. Two inputs usually tip the answer one way or the other. Identify which ones matter most by flipping each value past a round threshold and watching whether the winning option changes.

What's happening under the hood

SIM total is monthly × months + phone price. Contract total is monthly × months. Winner is lower total. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

What the bill doesn't show

Standing charges, discounts, and usage tiers all blur the effective rate. The calculation here backs out the total so you're comparing apples to apples across providers, regardless of how each one packages the price.

What this doesn't capture

Usage varies month-to-month; tariffs change; discounts come and go. The figure here is a clean baseline — your actual annual bill will fluctuate around it. Use the calculation to benchmark providers, not as a prediction of a specific bill.