Calculators
Each calculator shows its formula, units and assumptions. Nothing is estimated for you in secret.
Cost per use calculator
Turns a price into a cost per use, so a dear item used often can be compared with a cheap one used rarely.
cost per use = (price + consumables over the whole life) / (uses per week x 52 x years)
Assumptions
- Uses per week is assumed steady across the whole period.
- The item is assumed to last the number of years you enter, not longer.
The result is only as good as your estimate of how often you will really use it.
Routine cost calculator
How long a bottle lasts and what the routine costs per day, from dose and container size.
days per container = container size (ml) / (dose in ml x applications per day); cost per day = price / days per container
Assumptions
- A pump or dropper dose is assumed constant. Real doses vary, and a pea-sized amount is roughly 0.25 ml.
- Product left in the container at the end, and product discarded after its period-after-opening date, are not counted.
Dose is the biggest variable and the one the label rarely states in millilitres.
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.