Almost always, if the sign bit is 0, the number is non-negative (positive or zero).
Formats other than two's complement integers allow a signed zero: distinct "positive zero" and "negative zero" representations, the latter of which does not correspond to the mathematical concept of a negative number.
[3] Two's complement is by far the most common format for signed integers.
Due to this value being larger than all the other bits combined, having this bit set would ultimately make the number negative, thus changing the sign.
[citation needed] With an 8-bit integer, the sign bit would have a value of -(28-1 +1), or -127.