Paypal fees calculation

I just noticed that paypal has a fee. I’m using PHP (Philippine Peso) as a currency, so it is not that accurate when I manually convert the amount to USD just to add the paypal fees then convert it back to PHP.

Is there a way to automatically include it in the calculation before going to the actual paypal page?

The additional paypal fee is 2.9% + $0.3 per transactions.

Rather than converting to USD, making the addition, then converting back again, how about only converting 30 cents USD to PHP and adding that result to the percentage in PHP?
That’s just one conversion, and only converting what needs to be converted, so it should be more accurate.