Int8 -128 to 127 Two’s Complement Exactly 8 Bits Signed Integer

Signed 8-Bit Integer Decoder

Hex Int8 to Binary Converter

Convert a hexadecimal byte to its exact Int8 binary representation and signed decimal value. Values from 00–7F represent 0 through 127, while 80–FF represent -128 through -1 using standard 8-bit two’s complement.

Signed Int8 decoding 8-bit two’s complement Sign bit identified Signed decimal result

Hex → Int8 Binary

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HEX INT8 BIT PATTERN

Enter raw hex 00–FF · optional 0x prefix · sign comes from bit 7 · no external + or − sign

INT8 BINARY SIGNED 8-BIT

11111111

Hex: FF Sign bit: 1 Type: Int8

Signed decimal: -1

INT8 INTERPRETATION If bit 7 = 1, signed value = unsigned − 256

FF → 11111111 · sign bit 1 · unsigned 255 · 255 − 256 = -1

TRY:

Data Type Int8

Width 8 bits

Positive Range 00–7F → 0–127

Negative Range 80–FF → -128–-1

Encoding Two’s complement

Hex Int8 to Binary Converter

The Hex Int8 to Binary Converter converts a raw hexadecimal byte into its exact eight-bit binary pattern and interprets that pattern as a signed Int8 integer.

Int8 uses standard two’s-complement representation. Hex values from 00 through 7F represent non-negative values, while hexadecimal patterns from 80 through FF represent negative integers.

Example: hexadecimal FF converts to 11111111. Under Int8 two’s-complement interpretation this pattern represents -1.

What Is Int8?

Int8 means a signed integer stored in exactly eight bits. Because one bit is part of the signed two’s-complement representation, the range differs from UInt8.

Int8 width: 8 bits Minimum: 10000000 = -128 Maximum: 01111111 = 127

Hex Int8 Range

Every raw Int8 bit pattern can be written using two hexadecimal digits from 00 through FF, but those patterns do not all represent positive numbers.

Hex Range	Binary Range	Int8 Meaning
00–7F	00000000–01111111	0 to 127
80–FF	10000000–11111111	-128 to -1

How to Convert Hex Int8 to Binary

First convert each hexadecimal digit to four binary bits. The resulting eight-bit pattern is then interpreted using two’s-complement Int8 rules.

Example: FE F → 1111 E → 1110 Binary: 11111110 Unsigned pattern value: 254 Because bit 7 = 1: 254 − 256 = -2

Hex Int8 Conversion Examples

Hex	Int8 Binary	Signed Decimal
00	00000000	0
01	00000001	1
0A	00001010	10
7E	01111110	126
7F	01111111	127
80	10000000	-128
81	10000001	-127
FD	11111101	-3
FE	11111110	-2
FF	11111111	-1

Example: FF Hex as Int8

FF → 11111111 Sign bit: 1 Unsigned pattern: 255 Signed Int8: 255 − 256 = -1

This is why FF has a different numerical meaning on an Int8 page than on a UInt8 page.

Example: 80 Hex as Int8

80 → 10000000 Sign bit: 1 Unsigned pattern: 128 Int8 value: 128 − 256 = -128

Hex 80 is the smallest signed value representable by standard 8-bit two’s complement.

Example: 7F Hex as Int8

7F → 01111111 Sign bit: 0 Value: 127

7F is the largest positive Int8 value.

How the Int8 Sign Bit Works

The most significant bit is bit 7. When it is zero, the pattern represents a non-negative number. When it is one, the Int8 two’s-complement value is negative.

Bit positions: b7 b6 b5 b4 b3 b2 b1 b0 If b7 = 0: 0 through 127 If b7 = 1: -128 through -1

Int8 Signed Value Formula

For raw hexadecimal patterns, Int8 decoding can be expressed with a simple fixed-width formula.

Let U = unsigned value of the 8-bit pattern If U < 128: Int8 = U If U ≥ 128: Int8 = U − 256

For FE, U is 254, therefore 254 − 256 = -2.

Int8 vs UInt8

Int8 and UInt8 occupy the same eight bits but assign different numerical meanings to patterns whose highest bit is one.

Hex	Binary	UInt8	Int8
00	00000000	0	0
7F	01111111	127	127
80	10000000	128	-128
81	10000001	129	-127
FE	11111110	254	-2
FF	11111111	255	-1

Why Int8 Uses Two’s Complement

Two’s complement provides a convenient way to encode positive and negative integers in a fixed binary width while retaining a single representation for zero.

Positive 1: 00000001 Invert: 11111110 Add 1: 11111111 Therefore: FF = -1

Why Int8 Stops at 127

The positive side of an eight-bit signed two’s-complement integer ends at 01111111.

01111111 = 64 + 32 + 16 + 8 + 4 + 2 + 1 = 127

The next bit pattern, 10000000, crosses into the negative half and represents -128.

Why There Is No +128 in Int8

The eight-bit pattern 10000000 is reserved for -128 under two’s-complement interpretation. Int8 therefore cannot represent positive 128.

If you need hexadecimal 80 to mean positive 128, use UInt8 rather than Int8.

Why the Binary Output Always Has 8 Bits

Int8 is a fixed-width data type. Small positive values therefore still require all eight positions.

Hex	Minimal Binary	Int8 Binary	Int8 Value
1	1	00000001	1
A	1010	00001010	10
7F	1111111	01111111	127

Raw Int8 Hex Uses No Minus Sign

This calculator expects an encoded byte pattern such as FF or 80. The negative meaning is already contained in the two’s-complement bit pattern.

Correct raw Int8 pattern for -1: FF Binary: 11111111 Not: -FF

An external minus sign describes mathematical sign-and-magnitude notation, which is a different conversion task.

Optional 0x Prefix

One programming-style 0x or 0X prefix is accepted.

0xFE → FE → 11111110 → Int8 -2

Why Hex 100 Is Invalid for Int8

Int8 contains exactly eight raw bits. Hex 100 requires nine bits and cannot be stored as a single Int8 bit pattern.

FF: 11111111 = 8 bits 100: 100000000 = 9 bits Invalid Int8 raw pattern

Common Uses for Int8 Values

Signed one-byte sensor readings.
Embedded-system variables.
Binary file fields containing signed bytes.
Protocol fields with signed 8-bit values.
Audio and signal data.
Hardware register interpretation.
Firmware reverse engineering.
Low-level debugging.
Two’s-complement education.
Programming language integer conversion.

Common Hex Int8 Conversion Mistakes

Reading FF as 255 instead of Int8 -1.
Reading 80 as positive 128 instead of -128.
Using UInt8 rules for values with the high bit set.
Removing the fixed-width leading zero from positive values such as 7F.
Entering an external negative sign before the raw hex pattern.
Trying to fit hexadecimal 100 inside eight bits.
Using one’s-complement rules instead of two’s complement.
Confusing the raw binary pattern with its signed decimal interpretation.

Hex Int8 to Binary Converter FAQs

What is FF hex as Int8?

FF converts to 11111111 and represents -1 as an 8-bit signed two’s-complement integer.

What is FE hex as Int8?

FE converts to 11111110 and represents -2.

What is 80 hex as Int8?

80 converts to 10000000 and represents -128, the minimum Int8 value.

What is 7F hex as Int8?

7F converts to 01111111 and represents positive 127.

What is the Int8 range?

The signed Int8 range is -128 through 127.

Why does FF equal -1 instead of 255?

Int8 interprets 11111111 using signed two’s-complement rules. Its unsigned pattern value is 255, and 255 – 256 = -1.

Why does 80 equal -128?

The pattern 10000000 has its Int8 sign bit set. Its unsigned pattern value is 128, and 128 – 256 = -128.

Can Int8 represent positive 128?

No. Int8 ranges only from -128 to 127. Positive 128 requires UInt8 or a wider signed integer type.

Can I enter -1 as the hexadecimal input?

No. This converter accepts the raw Int8 hexadecimal bit pattern. The encoded representation for Int8 -1 is FF.

Can I enter 0xFF?

Yes. One optional 0x or 0X prefix is accepted.

Can I enter hexadecimal 100?

No. Hex 100 requires nine binary bits and cannot fit in Int8.

Is Int8 the same as one’s complement?

No. Standard Int8 interpretation uses two’s complement. For example FF is -1 in two’s complement, while an 8-bit one’s-complement FF pattern represents negative zero.

Convert Hex to Int8 Binary

Enter a raw hexadecimal byte from 00 through FF and select Convert Hex Int8. The calculator converts the byte to exactly eight binary digits, reads the most significant bit as the signed two’s-complement sign position and displays the correct Int8 decimal value from -128 through 127.