Keep or Sell Car Calculator

Keep or Sell? The Financial Analysis

People often trade in reliable cars because of repair bills, not realising that buying a different used car comes with unknown reliability and its own depreciation curve. This calculator compares the true financial cost of keeping vs replacing your vehicle.

The Costs People Often Overlook

Depreciation is one of those things that quietly drains money without ever sending you an invoice. A newer car loses value fastest in its early years, so replacing a well-depreciated vehicle with something newer can mean absorbing a steep drop in value almost immediately. It can help to think of depreciation as an invisible repair bill you pay whether anything goes wrong or not. Many people find that once they factor this in alongside finance interest, the maths shifts quite noticeably. This is worth noting before any final decision.

What the Numbers Do Not Always Capture

A calculator works with figures, but peace of mind has a value too. One approach is to treat the financial comparison as a starting point rather than the whole answer. If two options come out fairly close in cost, other factors like reliability history, practicality, and personal circumstances are entirely reasonable things to weigh alongside the estimate.

A worked example

Try the defaults: current car value of 8,000, expected annual repairs of 1,200, replacement car price of 20,000, finance rate of 8. The tool returns 8,599.00. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Current Car Value, Expected Annual Repairs, Replacement Car Price, Finance Rate, and Years to Compare. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

The formula behind this

This calculator compares total ownership costs over a specified period by adding current vehicle value and repair expenses against the net proceeds from selling plus depreciation on a replacement vehicle. Results assume constant annual repair costs, a fixed depreciation rate, and no transaction fees or taxes. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

Why run the numbers before the purchase

Big purchases reward slow thinking. The calculation here is fast; the decision it informs isn't. Running this before you shop is the cheapest way to avoid the "seemed fine in the showroom" trap.

What this doesn't capture

Purchase decisions rarely come down to payback alone. Reliability, time saved, enjoyment, and alternatives outside the calculation all matter. The figure gives you the money side cleanly so you can weigh it against everything else honestly.