Advanced options
Compare like with like: same handset, similar data. Contract prices typically rise mid-term with annual increases not included here. The classic trap is staying on a handset contract after the phone is paid off: switch to SIM-only the month it ends.
What The Phone Contract vs SIM-Only Calculator Works Out
- Contract total: the monthly price times the contract length. A phone contract is a handset loan wearing an airtime tariff, so GBP 45 a month for 24 months is GBP 1,080 before any upfront fee or mid-term rise.
- Buy + SIM-only total: the handset bought outright plus a SIM-only deal for the same months. The same GBP 700 phone plus a GBP 12 SIM comes to GBP 988, a GBP 92 gap in the default example. Refurbished handsets from reputable graders take 30% to 40% off near-new phones and pair naturally with SIM-only.
- Verdict: which route is cheaper and by how much. The contract's genuine advantages are cash flow and occasional real subsidies on last year's flagships; SIM-only's are price, one-month flexibility and immunity from the bundle's markup. Smaller networks using the big four's masts sell the same coverage at half the price.
- Upfront cost and cashback (advanced): add the upfront payment many contracts ask for and subtract cashback, gift cards or trade-in bonuses, so the contract total reflects the real deal rather than the headline monthly price.
- Annual price rises (advanced): since January 2025 Ofcom requires rises to be stated in pounds and pence rather than linked to inflation; GBP 1.50 to GBP 2.50 a month each April is typical. Enter the figure for each side and the totals step up on every anniversary, with the amount added shown separately.
- What the contract charges for the phone (advanced): the contract total minus equivalent SIM-only airtime, compared with the shop price. A figure well above the shop price is the bundle's markup; below it is a genuine subsidy worth taking.
- Equivalent APR (advanced): treats the monthly gap over SIM-only as repayments on a loan of the handset price and solves for the interest rate. Split contracts (handset credit agreement plus separate airtime) often run at 0% and show up on affordability checks as debt; an implied APR above about 25% is dearer than a typical UK credit card.
- Cost of staying on after it ends (advanced): the trap that funds the industry. Keeping a handset-inclusive tariff after month 24 means paying the phone's instalment forever on a phone already owned; this card prices each month of overrun. Text PAC to 65075 to switch; handsets are unlocked by default.
- Interest kept by spreading the cost (advanced): a rough value of keeping the handset money in savings and paying monthly instead: about half the price earning your savings rate across the term. Subtract it from the contract's extra cost for a fairer comparison. Not financial advice.
- Year-by-year table (advanced): what each route costs in each year, including any overrun, and the running gap between them. Families should take one strong SIM-only deal per person and buy phones on their own replacement cycle rather than the network's.