1 line of word = ... on graph paper

Your question makes no sense: You forgot to specify which font, what font size, and what line spacing, and what margins you're using in your word processor!
Because the answer varies from simple to tenfold depending on your settings.

So you do yourself what you're asking us to do for you:
You type a text with your software, write the same text on your checked sheet and compare it like a big boy...
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Retirement is nice! Especially in the Caribbean... :-)
☻ Raymond ♂

Good evening

Would you like us to write 10 lines for you?
You're likely to get varied responses, from those who write with tiny handwriting to those who write 5 words per line!

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Argitxu