How do I know my target gravity?

Hello all. Made a Bell's Two Hearted clone recently. The kit says the OG should be about 1064, my OG was 1060. It did not give me a target final gravity though. How exactly do you figure that out? I read through some posts on here but I'm really confused. I've already racked to the secondary (my final reading said 1018) so I'm more just curious for future reference.

Here's the recipe if that helps:

9.15 lbs Gold Malt Syrup extract
1 lb Briess Caramel 40 for steeping
1 oz Centennial hops for bitterness
1 oz Centennial hops flavor
2 oz Centennial hops for aroma
Wyeast #1084, Irish Ale yeast
1 oz Centennial hops for the dry hop

Thanks!

Nate,

Nice job getting so close to your OG. 1.018 sounds great. If you're worried, leave it for 3 days and check again. If it hasn't changed, you've hit your FG.

If you'd like, you could get a free evaluation copy of any beer program and put in your recipe. It will tell you your estimated OG and FG.

It depends on the OG, how fermentable the wort is and the yeast you used along with temperature etc.
100-(18/60*100)=70%

That's a little low for some yeast but its not far off.

Thanks!

So am I to understand that it's
100-[(FG/OG)*100]=Attenuation rate?

The Irish Ale rate comes in around 75% attenuation rate. So I'm off by 5%. Considering I didn't use a starter and my fermentation temps are about 5 degrees above recommended, that sounds good.