Everyday Money
Cost Comparison Calculator
Price and how long each option lasts — see the cheaper cost per year.
Cheap now or cheaper over time?
A dearer kettle that lasts eight years can beat a bargain that dies in two. This calculator spreads purchase price (and optional running costs such as energy, filters or ink) across expected lifespan or uses so you can compare ownership cost, not sticker price. Quality, repairability and hassle are not fully in the number — only the cash maths — but a clear annualised figure still stops many false economies. Warranty length and spare-part availability can change the real outcome after year three. For single-item use cost see cost per use; for electricity alone see appliance running cost. Bulk pantry maths lives on bulk buying savings. Illustrative only — not a consumer-rights assessment. Business buyers should also ask how downtime is valued when a cheap tool fails mid-job. Consumable lock-in — proprietary filters, batteries or ink — often decides the five-year winner after the purchase price has been forgotten. Write down your lifespan assumption so you can revisit it after a year of real use instead of defending a guess forever.
Worked example
Product A costs £30 and lasts 1 year (£30/year). Product B costs £70 and lasts 4 years (£17.50/year). B wins on annual cost even before replacement hassle — unless B uses £20 a year more in energy or cartridges. Add £15/year running cost to B and the annual totals become £30 versus £32.50, and A sneaks ahead on pure cash.
Limits and assumptions
Lifespan is a guess until you have brand history. Inflation on replacement prices is ignored. Environmental impact and data privacy of ‘smart’ replacements are outside the model.
Frequently asked questions
Should I include running costs?
Yes when they differ — energy, cartridges, bags or filters often dominate over years.
How do I estimate lifespan?
Use manufacturer guidance, reviews, or your own past experience with similar products. Stay conservative.
Can I compare buy versus repair?
Treat repair as a lower upfront cost with a shorter remaining life, then compare annualised cost.
What about interest-free finance?
If paying monthly changes what you can afford, compare total cash paid including any fees, not just the sticker.
How do returns and warranties fit?
A strong warranty can justify a higher purchase price; mentally shorten expected failure risk rather than forcing it into the formula.