Decimals
CosmWasm offers decimal types for handling fractional numbers.
In contrast to floating point numbers, these datatypes do not suffer from the same precision issues. This means that these decimal types are safe for use in financial calculations.
Instead of storing numbers in the floating point format, which gives it a floating amount of decimal places, these decimal types have a fixed precision of 18 decimal places.
Note that, due to how the decimal types are structured, the value ranges can seem a little weird.
For example, 1.0 is represented by Decimal(1_000_000_000_000_000_000) and the maximal value of the 128 bit variant is 340282366920938463463.374607431768211455 (which is (2^128 - 1) / 10^18)
In practice, you don't really have to think about it, but it's something you should be aware of.
Decimal types come in the following variants:
| Unsigned | Signed | |
|---|---|---|
| 128 bit | Decimal (opens in a new tab) | SignedDecimal (opens in a new tab) |
| 256 bit | Decimal256 (opens in a new tab) | SignedDecimal256 (opens in a new tab) |
Choose one of the types according to your needs and off you go!