In InkScape: FILE > SAVE AS > choose EPS from the format list.
UPDATE: The InkScape SAVE AS is not perfect and there may be some errors in the conversion. (Wanted to add this as a comment instead of editing the answer but there was no option for that) I used InkScape on Mac: FILE > SAVE AS > choose EPS from format list, while writing a paper which required EPS submission. However I found that there were some errors in the conversion.
