The real cost is the amount lost over the period you use the phone, not the number printed beside it at checkout. Build the figure from written payments and conservative assumptions.
Use five buckets
| Bucket | Include |
|---|---|
| Acquire | Cash price, deposit and every device instalment |
| Connect | Airtime, stated price rises and unavoidable service charges |
| Protect | Case, screen protection, insurance premiums and excess |
| Maintain | Battery, repair, replacement cable and diagnostic costs |
| Recover | Net sale, trade-in or recycling value |
Illustrative three-year calculation
A phone costing £520, a £9 monthly SIM, £38 of initial accessories and a £70 repair reserve totals £952 over three years. If £110 is recovered at sale, the illustrative net cost is £842, or about £23.39 per month. The example is not current market data.
Run a no-resale version
Future resale is uncertain. If the purchase is unaffordable without an optimistic resale figure, the model is too fragile. Also run the result with £0 recovered and with one expected repair.
Compare value per useful year
Divide the net cost by the realistic number of useful years, not the longest imaginable lifespan. Security support, battery service, storage and physical durability determine whether the planned period is credible.
What not to include
Do not add the original list price when you paid a lower transaction price. Do not count an accessory twice because it appears in a bundle. Do not subtract a trade-in quote that has already been used as an upfront discount and then subtract it again as resale.
Use the calculation to choose, not justify
Run the numbers before becoming attached to a model. If the preferred phone is more expensive, identify the exact benefit being purchased. A deliberate premium can be reasonable; an unexplained premium is merely overspend.
Related guides
- Smartphone Cost of Ownership Guide
- Hidden Costs of Phone Ownership
Sources and date checked
Official information checked 26 July 2026. Product prices, contract terms and retailer policies can change, so verify the current document before acting.
