## Calculations​

### Calculation of monthly cost for account.​

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 200 SEK, divided on 12 months, an interest rate of 1,6583%, and a monthly fee of 35 SEK would give the algorithm:

`(200 / 12) + (200 * 1,6583%) + 35 = 55 SEK 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 50 SEK.

### Calculating monthly cost to display on check-out page​

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 worth 195 SEK and a shipping fee of 59 SEK is added. This algorithm would then apply:

`(449 / 12) + (449 * 1,6583%) + 35 = 80 SEK 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 50 SEK.

### Calculation of monthly cost for interest free part payment.​

The formula used to calculate the cost is as follows:

`(Order sum + (Invoice fee * months)) / months`

Here's an example: if the total basket value is 3456 SEK, it would give the following calculation:

`(3456 + (35 * 12)) / 12 = 323kr/month`

Please note that an origination fee is added to the first invoice. The standard set of instalment plans and their origination fees and interest rates can be found in the table below, however, please refer to your merchant agreement with Walley to get the correct origination fee amounts.

Using the example amount above and an origination fee of 295 SEK, a first invoices lowest amount to pay would be 323 + 295 = 618 SEK.

### Calculation of monthly cost for annuity payment​

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 3456 SEK, it would give the following calculation:

`3456 _ (1,6583% / ((1 + 1,6583%) ^ 24 - 1)) + 3456 _ 1,6583% +35 = 215 SEK/month`

PLEASE NOTE Please note that an origination fee is added to the first invoice. The standard set of instalment plans and their origination fees and interest rates can be found in the table below, however, please refer to your merchant agreement with Walley to get the correct origination fee amounts.

Using the example amount above and an origination fee of 295 SEK, a first invoices lowest amount to pay would be 215 + 295 = 510 SEK.

Please note that the amount to pay per month should be rounded up to the nearest integer, and the lowest amount is always 50 SEK.