IBM z/OS Mainframe Binary & Character Translation Suite

EBCDIC to ASCII & COMP-3 Packed Decimal Decoder

Translate raw IBM EBCDIC hex dumps, decode binary-coded decimal (COMP-3) signed nibbles, and inspect zoned decimal overpunches.

Strategic Context & How To Use:

Mainframes store characters in EBCDIC (IBM-037/1047) and store numbers in packed decimal (`COMP-3`), where each byte holds two BCD digits and the final nibble stores the sign (`C`=positive, `D`=negative, `F`=unsigned). For example, hex bytes `00 12 34 5C` with implicit decimal `V99` unpacks to exactly `+$123.45`. Use the tabs below to decode raw hex buffers or pack modern numbers into mainframe binary.

Input Stream

Input Format & Data:

Input is EBCDIC Hex Bytes Input is ASCII Text (Encode to EBCDIC)

Translated Output

Decoded ASCII / UTF-8 Text:

EBCDIC Hex Representation:

Total Byte Length: 0 Bytes Code Page: IBM-037

COMP-3 Hex Unpacker (Mainframe → Number)

Paste raw hex bytes from an IBM MQ packet or VSAM dataset.

Raw COMP-3 Hex Bytes:

Implicit Decimals (PIC V):

Storage Allocation:

4 Bytes (7 Digits + Sign)

Decoded Decimal Value: Positive (C)

+123.45

Nibbles: [0][0] [1][2] [3][4] [5][C=Sign]

COMP-3 Hex Packer (Number → Mainframe Hex)

Encode numbers into packed BCD bytes for transmission to z/OS.

Enter Target Number (Positive or Negative):

Target Total Digits:

Sign Nibble Format:

Generated COMP-3 Hex Bytes:

00 85 40 25 D

COBOL Matching Definition: PIC S9(5)V99 COMP-3.

Zoned Decimal (Signed Overpunch) Conversion Matrix

In standard COBOL `DISPLAY` numeric records (`PIC S9(5)`), the sign is encoded into the high-order nibble of the last digit (signed overpunch). Use the decoder table below:

Positive Sign Overpunches (0xC0 in EBCDIC)

Digit	ASCII Char	EBCDIC Hex	Example (1234[X])
+0	{	0xC0	1234{ = +12340
+1	A	0xC1	1234A = +12341
+2	B	0xC2	1234B = +12342
+3	C	0xC3	1234C = +12343
+4	D	0xC4	1234D = +12344
+5	E	0xC5	1234E = +12345
+6	F	0xC6	1234F = +12346
+7	G	0xC7	1234G = +12347
+8	H	0xC8	1234H = +12348
+9	I	0xC9	1234I = +12349

Negative Sign Overpunches (0xD0 in EBCDIC)

Digit	ASCII Char	EBCDIC Hex	Example (1234[X])
-0	}	0xD0	1234} = -12340
-1	J	0xD1	1234J = -12341
-2	K	0xD2	1234K = -12342
-3	L	0xD3	1234L = -12343
-4	M	0xD4	1234M = -12344
-5	N	0xD5	1234N = -12345
-6	O	0xD6	1234O = -12346
-7	P	0xD7	1234P = -12347
-8	Q	0xD8	1234Q = -12348
-9	R	0xD9	1234R = -12349

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