Well, there are a few ways to answer this question. The guinea was a gold British machine struck coin that eventually had the value of 1 pound and 1 shilling. In the pre-decimal system there were 20 shillings to the pound and 12 pence to the shilling. Eventually the guinea was superseded by the sovereign, a gold coin worth 1 pound.
The difficulty in answering your question is that the guinea no longer really exists, technically it would be worth 1.10 pounds if you did a straight conversion of currency and converting the pre-decimal amount to the post-decimal amount, which would equal to about $1.76 US.
However, since neither the UK or the US is on the gold standard anymore, the actual price of a gold guinea is much, much higher than $1.76, also, the pound has been devalued much more to the US than historically (historically there have been about 4 pounds in each US dollar, or about 5 shillings to the dollar). So if you have a physical guinea, post a new question including the date and an estimate of condition and we can find you a value for that coin.
The guinea coin was not made after 1816.
1 penny
If you know how much 21 shillings are worth in Australian dollars you'll know how much a guinea is worth in Australian dollars, hoped this helped (I'm pretty sure it didn't though!)
Ten dollars is worth $10, it does not matter where you take it.
The kina is the currency of Papua New Guinea. It is divided into 100 toea.
depends on the age. Save
A guinea today is worth £1.05.
Communaute Financiere Africaine franc
A British Guinea was worth 21 Shillings or One Pound and One Shilling.
In the old currency, One Guinea was equal to 21 Shillings or One Pound and One Shilling. In the new currency, One Guinea is equal to One Pound and Five Pence.
Abbyssinian guinea pigs range from $20 to 40$ in cost. It is worth it though. They might be just the cutest, nicest, and cuddliest guinea pigs of all. Strait haired guinea pigs usually cost about the same. I recommend if you are buying a guinea pig to shop at a pet store such as PETCO and PETSMART. ----
A guinea is still £1.05 (21 shillings)