Formula for estimating SG from sugar content?

[Huntsekker]

Hi everyone

I was advised to repost this over from a cider thread (since more people read this area and the question applies equally regardless of brew), so here we go:

Thread here for reference: http://www.thehomebrewforum.co.uk/showthread.php?t=53809

Question:
If I know the weight of sugar against the volume in my fermenter, can anyone give me the formula used to calculate % potential?

TIA

Edit: I found a few cool tools in BrewMate that give me what I need, but I would still like to understand the maths and not rely on a tool.

 

[clibit]

The answer is here...

http://homebrew.stackexchange.com/questions/1434/wiki-how-do-you-calculate-original-gravity

 

[Huntsekker]

The answer is here...

http://homebrew.stackexchange.com/questions/1434/wiki-how-do-you-calculate-original-gravity

Thanks :thumb:

 

[Twostage]

Note that those calculations are for US gallons.

If my maths is right :-

1 US gal = 3.785 litres
1 lb = .454 kilo

So convert the US style to a useful metric style you can convert things to gravity points in kilos and 10 litres you end up with multiplying the US gravity by .8337 (3.785 divided by .454).
So if 1 lb of sugar gives 46 points in one US gallon then 1 kilo of sugar gives 38.3 points in 10 litres. Or 77 in 5 litres.

Can a teacher check my maths ?