Units

Common units

• wei is the smallest subdenomination of Ether (1 wei == 1)

• gwei is the commonly used subdenomination to describe gas price (1 gwei == 1e9)

• ether unit (1 ether == 1e18)

Note

In Solidity, we will use integers for calculations and the language does not support the float type. The float representation issue causes rounding errors (rounding) that create logical holes for attack.

Time units

• 1 == 1 seconds

• 1 minutes == 60 seconds

• 1 hours == 60 minutes

• 1 days == 24 hours

• 1 weeks == 7 days

Example

function f(uint start, uint daysAfter) public {
    if (block.timestamp >= start + daysAfter * 1 days) {
        // ...
    }
}