A number base, or radix, is how many digits a system uses to write numbers. Decimal (base 10) uses 0 to 9; binary (base 2) uses 0 and 1; octal (base 8) uses 0 to 7; and hexadecimal (base 16) uses 0 to 9 then A to F. Computers work in binary, so binary, octal, and hex appear everywhere in programming. This table converts every value from 0 to 255 across all four bases.
| Decimal | Binary (8-bit) | Octal | Hex |
|---|---|---|---|
0 |
00000000 |
0 |
0 |
1 |
00000001 |
1 |
1 |
2 |
00000010 |
2 |
2 |
3 |
00000011 |
3 |
3 |
4 |
00000100 |
4 |
4 |
5 |
00000101 |
5 |
5 |
6 |
00000110 |
6 |
6 |
7 |
00000111 |
7 |
7 |
8 |
00001000 |
10 |
8 |
9 |
00001001 |
11 |
9 |
10 |
00001010 |
12 |
A |
11 |
00001011 |
13 |
B |
12 |
00001100 |
14 |
C |
13 |
00001101 |
15 |
D |
14 |
00001110 |
16 |
E |
15 |
00001111 |
17 |
F |
16 |
00010000 |
20 |
10 |
17 |
00010001 |
21 |
11 |
18 |
00010010 |
22 |
12 |
19 |
00010011 |
23 |
13 |
20 |
00010100 |
24 |
14 |
21 |
00010101 |
25 |
15 |
22 |
00010110 |
26 |
16 |
23 |
00010111 |
27 |
17 |
24 |
00011000 |
30 |
18 |
25 |
00011001 |
31 |
19 |
26 |
00011010 |
32 |
1A |
27 |
00011011 |
33 |
1B |
28 |
00011100 |
34 |
1C |
29 |
00011101 |
35 |
1D |
30 |
00011110 |
36 |
1E |
31 |
00011111 |
37 |
1F |
32 |
00100000 |
40 |
20 |
33 |
00100001 |
41 |
21 |
34 |
00100010 |
42 |
22 |
35 |
00100011 |
43 |
23 |
36 |
00100100 |
44 |
24 |
37 |
00100101 |
45 |
25 |
38 |
00100110 |
46 |
26 |
39 |
00100111 |
47 |
27 |
40 |
00101000 |
50 |
28 |
41 |
00101001 |
51 |
29 |
42 |
00101010 |
52 |
2A |
43 |
00101011 |
53 |
2B |
44 |
00101100 |
54 |
2C |
45 |
00101101 |
55 |
2D |
46 |
00101110 |
56 |
2E |
47 |
00101111 |
57 |
2F |
48 |
00110000 |
60 |
30 |
49 |
00110001 |
61 |
31 |
50 |
00110010 |
62 |
32 |
51 |
00110011 |
63 |
33 |
52 |
00110100 |
64 |
34 |
53 |
00110101 |
65 |
35 |
54 |
00110110 |
66 |
36 |
55 |
00110111 |
67 |
37 |
56 |
00111000 |
70 |
38 |
57 |
00111001 |
71 |
39 |
58 |
00111010 |
72 |
3A |
59 |
00111011 |
73 |
3B |
60 |
00111100 |
74 |
3C |
61 |
00111101 |
75 |
3D |
62 |
00111110 |
76 |
3E |
63 |
00111111 |
77 |
3F |
64 |
01000000 |
100 |
40 |
65 |
01000001 |
101 |
41 |
66 |
01000010 |
102 |
42 |
67 |
01000011 |
103 |
43 |
68 |
01000100 |
104 |
44 |
69 |
01000101 |
105 |
45 |
70 |
01000110 |
106 |
46 |
71 |
01000111 |
107 |
47 |
72 |
01001000 |
110 |
48 |
73 |
01001001 |
111 |
49 |
74 |
01001010 |
112 |
4A |
75 |
01001011 |
113 |
4B |
76 |
01001100 |
114 |
4C |
77 |
01001101 |
115 |
4D |
78 |
01001110 |
116 |
4E |
79 |
01001111 |
117 |
4F |
80 |
01010000 |
120 |
50 |
81 |
01010001 |
121 |
51 |
82 |
01010010 |
122 |
52 |
83 |
01010011 |
123 |
53 |
84 |
01010100 |
124 |
54 |
85 |
01010101 |
125 |
55 |
86 |
01010110 |
126 |
56 |
87 |
01010111 |
127 |
57 |
88 |
01011000 |
130 |
58 |
89 |
01011001 |
131 |
59 |
90 |
01011010 |
132 |
5A |
91 |
01011011 |
133 |
5B |
92 |
01011100 |
134 |
5C |
93 |
01011101 |
135 |
5D |
94 |
01011110 |
136 |
5E |
95 |
01011111 |
137 |
5F |
96 |
01100000 |
140 |
60 |
97 |
01100001 |
141 |
61 |
98 |
01100010 |
142 |
62 |
99 |
01100011 |
143 |
63 |
100 |
01100100 |
144 |
64 |
101 |
01100101 |
145 |
65 |
102 |
01100110 |
146 |
66 |
103 |
01100111 |
147 |
67 |
104 |
01101000 |
150 |
68 |
105 |
01101001 |
151 |
69 |
106 |
01101010 |
152 |
6A |
107 |
01101011 |
153 |
6B |
108 |
01101100 |
154 |
6C |
109 |
01101101 |
155 |
6D |
110 |
01101110 |
156 |
6E |
111 |
01101111 |
157 |
6F |
112 |
01110000 |
160 |
70 |
113 |
01110001 |
161 |
71 |
114 |
01110010 |
162 |
72 |
115 |
01110011 |
163 |
73 |
116 |
01110100 |
164 |
74 |
117 |
01110101 |
165 |
75 |
118 |
01110110 |
166 |
76 |
119 |
01110111 |
167 |
77 |
120 |
01111000 |
170 |
78 |
121 |
01111001 |
171 |
79 |
122 |
01111010 |
172 |
7A |
123 |
01111011 |
173 |
7B |
124 |
01111100 |
174 |
7C |
125 |
01111101 |
175 |
7D |
126 |
01111110 |
176 |
7E |
127 |
01111111 |
177 |
7F |
128 |
10000000 |
200 |
80 |
129 |
10000001 |
201 |
81 |
130 |
10000010 |
202 |
82 |
131 |
10000011 |
203 |
83 |
132 |
10000100 |
204 |
84 |
133 |
10000101 |
205 |
85 |
134 |
10000110 |
206 |
86 |
135 |
10000111 |
207 |
87 |
136 |
10001000 |
210 |
88 |
137 |
10001001 |
211 |
89 |
138 |
10001010 |
212 |
8A |
139 |
10001011 |
213 |
8B |
140 |
10001100 |
214 |
8C |
141 |
10001101 |
215 |
8D |
142 |
10001110 |
216 |
8E |
143 |
10001111 |
217 |
8F |
144 |
10010000 |
220 |
90 |
145 |
10010001 |
221 |
91 |
146 |
10010010 |
222 |
92 |
147 |
10010011 |
223 |
93 |
148 |
10010100 |
224 |
94 |
149 |
10010101 |
225 |
95 |
150 |
10010110 |
226 |
96 |
151 |
10010111 |
227 |
97 |
152 |
10011000 |
230 |
98 |
153 |
10011001 |
231 |
99 |
154 |
10011010 |
232 |
9A |
155 |
10011011 |
233 |
9B |
156 |
10011100 |
234 |
9C |
157 |
10011101 |
235 |
9D |
158 |
10011110 |
236 |
9E |
159 |
10011111 |
237 |
9F |
160 |
10100000 |
240 |
A0 |
161 |
10100001 |
241 |
A1 |
162 |
10100010 |
242 |
A2 |
163 |
10100011 |
243 |
A3 |
164 |
10100100 |
244 |
A4 |
165 |
10100101 |
245 |
A5 |
166 |
10100110 |
246 |
A6 |
167 |
10100111 |
247 |
A7 |
168 |
10101000 |
250 |
A8 |
169 |
10101001 |
251 |
A9 |
170 |
10101010 |
252 |
AA |
171 |
10101011 |
253 |
AB |
172 |
10101100 |
254 |
AC |
173 |
10101101 |
255 |
AD |
174 |
10101110 |
256 |
AE |
175 |
10101111 |
257 |
AF |
176 |
10110000 |
260 |
B0 |
177 |
10110001 |
261 |
B1 |
178 |
10110010 |
262 |
B2 |
179 |
10110011 |
263 |
B3 |
180 |
10110100 |
264 |
B4 |
181 |
10110101 |
265 |
B5 |
182 |
10110110 |
266 |
B6 |
183 |
10110111 |
267 |
B7 |
184 |
10111000 |
270 |
B8 |
185 |
10111001 |
271 |
B9 |
186 |
10111010 |
272 |
BA |
187 |
10111011 |
273 |
BB |
188 |
10111100 |
274 |
BC |
189 |
10111101 |
275 |
BD |
190 |
10111110 |
276 |
BE |
191 |
10111111 |
277 |
BF |
192 |
11000000 |
300 |
C0 |
193 |
11000001 |
301 |
C1 |
194 |
11000010 |
302 |
C2 |
195 |
11000011 |
303 |
C3 |
196 |
11000100 |
304 |
C4 |
197 |
11000101 |
305 |
C5 |
198 |
11000110 |
306 |
C6 |
199 |
11000111 |
307 |
C7 |
200 |
11001000 |
310 |
C8 |
201 |
11001001 |
311 |
C9 |
202 |
11001010 |
312 |
CA |
203 |
11001011 |
313 |
CB |
204 |
11001100 |
314 |
CC |
205 |
11001101 |
315 |
CD |
206 |
11001110 |
316 |
CE |
207 |
11001111 |
317 |
CF |
208 |
11010000 |
320 |
D0 |
209 |
11010001 |
321 |
D1 |
210 |
11010010 |
322 |
D2 |
211 |
11010011 |
323 |
D3 |
212 |
11010100 |
324 |
D4 |
213 |
11010101 |
325 |
D5 |
214 |
11010110 |
326 |
D6 |
215 |
11010111 |
327 |
D7 |
216 |
11011000 |
330 |
D8 |
217 |
11011001 |
331 |
D9 |
218 |
11011010 |
332 |
DA |
219 |
11011011 |
333 |
DB |
220 |
11011100 |
334 |
DC |
221 |
11011101 |
335 |
DD |
222 |
11011110 |
336 |
DE |
223 |
11011111 |
337 |
DF |
224 |
11100000 |
340 |
E0 |
225 |
11100001 |
341 |
E1 |
226 |
11100010 |
342 |
E2 |
227 |
11100011 |
343 |
E3 |
228 |
11100100 |
344 |
E4 |
229 |
11100101 |
345 |
E5 |
230 |
11100110 |
346 |
E6 |
231 |
11100111 |
347 |
E7 |
232 |
11101000 |
350 |
E8 |
233 |
11101001 |
351 |
E9 |
234 |
11101010 |
352 |
EA |
235 |
11101011 |
353 |
EB |
236 |
11101100 |
354 |
EC |
237 |
11101101 |
355 |
ED |
238 |
11101110 |
356 |
EE |
239 |
11101111 |
357 |
EF |
240 |
11110000 |
360 |
F0 |
241 |
11110001 |
361 |
F1 |
242 |
11110010 |
362 |
F2 |
243 |
11110011 |
363 |
F3 |
244 |
11110100 |
364 |
F4 |
245 |
11110101 |
365 |
F5 |
246 |
11110110 |
366 |
F6 |
247 |
11110111 |
367 |
F7 |
248 |
11111000 |
370 |
F8 |
249 |
11111001 |
371 |
F9 |
250 |
11111010 |
372 |
FA |
251 |
11111011 |
373 |
FB |
252 |
11111100 |
374 |
FC |
253 |
11111101 |
375 |
FD |
254 |
11111110 |
376 |
FE |
255 |
11111111 |
377 |
FF |
Frequently Asked Questions
Why do computers use binary?
Hardware stores information as on/off states, which map naturally to the two binary digits 0 and 1.
Why use hexadecimal instead of binary?
Hex is much shorter and each hex digit equals four binary digits, so it is easier to read and write while still mapping cleanly to binary.
How do I read an 8-bit binary number?
Each position is a power of two, from 128 on the left down to 1 on the right. Add the positions that show a 1 to get the decimal value.
What is the range of one byte?
One byte is 8 bits, which holds 256 values, from 0 to 255 in decimal or 00 to FF in hexadecimal.
Convert your own values with our free base converters, or see the ASCII table for character codes.