## Calculationsâ€‹

### Calculation of monthly cost for account.â€‹

You can use the following algorithm to calculate the products part payment cost (in the end customers native currency):

`(Product cost / Number of months) + (Product cost * Interest rate) + Monthly fee`

For example: A product worth 9,95 â‚¬ , divided on 12 months, an interest rate of 1,6583 %, and a monthly fee of 3,00 â‚¬ would give the algorithm:

`(9,95 / 12) + (9,95 * 1,6583 %) + 3,00 = 4,00 â‚¬ per month`

(The actual lowest amount to pay in the example would be 4,00 â‚¬ per month, but the lowest accepted payment is 5 â‚¬)

### Calculating monthly cost to display on the checkout pageâ€‹

The same algorithm can be applied on the checkout page, but the two occurrences of product cost needs to be replaced by the total purchase amount including shipping fee:

`(Total purchase amount / Number of months) + (Total purchase amount * Interest rate) + Monthly fee`

For example: The customer orders two products, each worth 19,90 â‚¬ and a shipping fee of 5,95 â‚¬ is added. This algorithm would then apply:

`(45,75 / 12) + (45,75 * 1,6583 %) + 3,00 = 7,58 â‚¬ per month`

Please note that the amount to pay per month should be rounded up to the nearest integer, and the lowest amount is always 5 â‚¬.

### Calculation of monthly cost for annuity paymentâ€‹

The formula used to calculate the cost is the following:

`CapitalDebt * (MonthlyInterestRate / ((1 + MonthlyInterestRate) ^ Months - 1)) + CapitalDebt * MonthlyInterestRate + InvoiceFee`

Here's an example: if the total basket value is 321,8â‚¬, it gives the following:

`321,8 * (1,6583% / ((1 + 1,6583%) ^ 24 - 1)) + 321,8 * 1,6583% +3,00 = 19,37â‚¬ per month`

Please note that the amount to pay per month should be rounded up to the nearest integer, and the lowest amount is always 5 â‚¬.