Calculators
Each calculator shows its formula, units and assumptions. Nothing is estimated for you in secret.
Cost per year calculator
Spreads purchase price, consumables and repairs over the years you expect to keep it.
cost per year = (purchase price - expected resale value + consumables per year x years + expected repairs) / years
Assumptions
- Resale value is your own estimate. Nothing here predicts a used-market price.
- No discounting or inflation is applied: a cost in year five counts the same as a cost today.
A planning figure for comparing two purchases, not an accounting depreciation schedule.
Consumable interval and cost
Replacement intervals turned into a yearly cost for filters, pads, pods and brush heads.
replacements per year = 365 / interval in days; yearly cost = replacements per year x unit price x units per change
Assumptions
- The interval is the one you enter. Manufacturer intervals assume a usage level printed in the manual.
- Hard water, pets and heavy use shorten most intervals.
Intervals from a manual are a starting point; the real one depends on your water, air and use.
Landed cost calculator
What a cross-border order really costs once shipping, duty and tax are added.
landed cost = (item price + shipping) + duty + tax, where duty = item price x duty rate, and tax = (item price + shipping + duty) x tax rate
Assumptions
- Duty is applied to the item price only; tax is applied to item price plus shipping plus duty. Some countries tax shipping differently, and a few apply duty to the shipping too.
- Rates are the ones you enter. This calculator does not know your country's current duty schedule or de minimis threshold.
- Currency conversion, card fees and any prepayment discount are not included.
This is arithmetic on your own figures, not a customs ruling. The carrier or customs authority decides the final amount.