If you have several files that need to be converted to utf8, you can do it with vim.

First start vim with:

$ vim $(find . -type f -iname '*.htm*')

Which will find all .htm and .html files from the current directory.

Then in vim, use : to go into command mode.

Run these two commands:
:set nomore
:bufdo set fileencoding=utf8 | w

Reference:
https://stackoverflow.com/questions/4544669/batch-convert-latin-1-files-to-utf-8-using-iconv