Use Singpost's online postage calculator. You'll need to choose your destination from the drop down button and input the weight of your mail at http://singpost.com/quick_services/quicks_02postage_cal.asp .
As for mailing from the US, I found this link which could be of help to you : ircalc.usps.gov
Hope this helps =)
Regards,
Sarah ZA
As for mailing from the US, I found this link which could be of help to you : ircalc.usps.gov
Hope this helps =)
Regards,
Sarah ZA