Yep, it is 5:1. 60-12 teeth..
(Attached is my calculator spreadsheet).
My pulleys came from SDP-Si:
http://shop.sdp-si.com/catalog/produ...A51M012DF0603#
http://shop.sdp-si.com/catalog/produ...6A51M060DF0606
(BTW, SPI-SI catalogue says GT2 60t pulley pitch diameter is ø38.2mm, with belt this is ~same as 47-teeth gear... maybe your ø44mm is with flanges? You don't really need them, belt will not slip from pulley if everithing is square and because it will be guided by slot in the enclosure).