Technically it's 15:1, but I'm avoiding fractions until I've added in other denominations.
Coin Name: Number of coins it takes to equal more valuable coins :: Material coin is made from :: Approximate mass of coin in grams
Ator: 5 ators to a sult :: Cast from brass:: ~8 g
Sult: 5 sults to a cersage :: Cast from copper :: ~10 g :: Roughly two Sult for one loaf of bread in Denierilc
Cersage: 3 cersages to a quil :: Cast from brass :: ~15 g
Quil: 5 quils to a tanid :: Cast from silver :: ~3 g
Tanid: Cast from gold :: ~5 g
So... 1 Tanid = 5 Quil = 15 Cersage = 75 Sult = 375 Ator?
Isn't this just a little excessive? I can understand two currencies with denotions of 10 (1g = 10s and 1T = 10Q where 1T = 3g), but 5 separate coins with varying exchange rates is really weird for a tabletop game.
EDIT: Thanks Darvi.
If one tries this in base 15 then you get:
1 Tanid = 5 quil = 10 Cersage = 50 Sult = 250 Ator which is sort of workable if you have 4 hands and use three of them to count and one to beat the taxes out of the rabble...
You should have seen pre-decimal British money.
1 pound = 8 Half Crowns = 10 florins = 20 shillings = 40 sixpence coins = 80 threepence coins = 240 pence = 480 halfpenny coins
The British one actually makes a lot of sense if you discount halfcrowns+pounds and operate on base twelve, which makes a lot of sense if you are not used to base 10...
12/2 halfpennies = 12 pence = 4 threepence = 2 sixpence = 1 shilling = 1/2 florin.
So a shilling is 12 pence and the mid denominations are halves, and the halfpenny is a half of a penny if you want to discriminate at that level, while a florin is just two shilling...
The higher denominations are a bit odd though, a pound is ten florins and looks as though it was added to deal with large numbers.
Half-crowns are a bit odd , but assuming that two halfcrowns make one crown, then a crown would be five shilling or sixty pence, sixty, of course, would be fifty in base twelve...
If you are trying to use all ofthem then it gets complicated, but crowns are fine by themselves and can mix with pennies if you are willing to sully yourself with such amounts. Pennies are great for lots of small transactions, once you are used to base twelve... And the only people using pounds are likely to be tourists who won't be seeing any change anyway so it doesn't matter...
I would see the Cersage<->Quil conversion being a sticking point, with wealthier folk not wanting to deal with amounts smaller than a quil and the less influential tending not to deal in quils except when making transactions that involve the bourgeois...
It would be nice to see more base twelve, base ten has the issue that ten can only be divided by 3/10 digits, where as twelve works with 5/12, a much higher proportion...