WormFood's AVR Baud Rate Calculator Ver. 1.1.0

Bit Rate	UBRR	% of error
32.768 Khz
300	6	2.5
600	2	12.1
1200	1	17.2
2400	0	17.2
4800	0	134.4
9600	0	368.8
14400	0	603.1
19200	0	837.5
28800	0	1306.2
38400	0	1775.0
57600	0	2712.5
76800	0	3650.0
115200	0	5525.0
230400	0	11150.0

Bit Rate	UBRR	% of error
1.8432 Mhz
300	383	0.0
600	191	0.0
1200	95	0.0
2400	47	0.0
4800	23	0.0
9600	11	0.0
14400	7	0.0
19200	5	0.0
28800	3	0.0
38400	2	0.0
57600	1	0.0
76800	1	33.3
115200	0	0.0
230400	0	100.0

Bit Rate	UBRR	% of error
2.4576 Mhz
300	511	0.0
600	255	0.0
1200	127	0.0
2400	63	0.0
4800	31	0.0
9600	15	0.0
14400	10	3.1
19200	7	0.0
28800	4	6.2
38400	3	0.0
57600	2	12.5
76800	1	0.0
115200	0	25.0
230400	0	50.0

Bit Rate	UBRR	% of error
3.072 Mhz
300	639	0.0
600	319	0.0
1200	159	0.0
2400	79	0.0
4800	39	0.0
9600	19	0.0
14400	12	2.5
19200	9	0.0
28800	6	5.0
38400	4	0.0
57600	2	10.0
76800	2	20.0
115200	1	20.0
230400	0	20.0

Bit Rate	UBRR	% of error
3.2768 Mhz
300	682	0.0
600	340	0.1
1200	170	0.2
2400	84	0.4
4800	42	0.8
9600	20	1.6
14400	13	1.6
19200	10	3.1
28800	6	1.6
38400	4	6.2
57600	3	12.5
76800	2	12.5
115200	1	12.5
230400	0	12.5

Bit Rate	UBRR	% of error
3.579545 Mhz
300	745	0.0
600	372	0.0
1200	185	0.2
2400	92	0.2
4800	46	0.8
9600	22	1.3
14400	15	3.0
19200	11	3.0
28800	7	3.0
38400	5	3.0
57600	3	3.0
76800	2	3.0
115200	1	3.0
230400	0	3.0

Bit Rate	UBRR	% of error
3.6864 Mhz
300	767	0.0
600	383	0.0
1200	191	0.0
2400	95	0.0
4800	47	0.0
9600	23	0.0
14400	15	0.0
19200	11	0.0
28800	7	0.0
38400	5	0.0
57600	3	0.0
76800	2	0.0
115200	1	0.0
230400	0	0.0

Bit Rate	UBRR	% of error
3.93216 Mhz
300	818	0.0
600	409	0.1
1200	204	0.1
2400	101	0.4
4800	50	0.4
9600	25	1.6
14400	16	0.4
19200	12	1.6
28800	8	5.5
38400	5	6.2
57600	3	6.2
76800	2	6.2
115200	1	6.2
230400	0	6.2

Bit Rate	UBRR	% of error
4 Mhz
300	832	0.0
600	416	0.1
1200	207	0.2
2400	103	0.2
4800	51	0.2
9600	25	0.2
14400	16	2.1
19200	12	0.2
28800	8	3.7
38400	6	7.5
57600	3	7.8
76800	2	7.8
115200	1	7.8
230400	0	7.8

Bit Rate	UBRR	% of error
4.194304 Mhz
300	873	0.0
600	436	0.0
1200	217	0.2
2400	108	0.2
4800	54	0.7
9600	26	1.1
14400	17	1.1
19200	13	2.5
28800	8	1.1
38400	6	2.5
57600	4	9.9
76800	2	12.1
115200	1	12.1
230400	0	12.1

Bit Rate	UBRR	% of error
4.433619 Mhz
300	923	0.0
600	461	0.0
1200	230	0.0
2400	114	0.4
4800	57	0.5
9600	28	0.5
14400	18	1.3
19200	13	3.0
28800	9	3.9
38400	6	3.0
57600	4	3.9
76800	3	10.9
115200	1	16.9
230400	0	16.9

Bit Rate	UBRR	% of error
4.608 Mhz
300	959	0.0
600	479	0.0
1200	239	0.0
2400	119	0.0
4800	59	0.0
9600	29	0.0
14400	19	0.0
19200	14	0.0
28800	9	0.0
38400	7	6.7
57600	4	0.0
76800	3	6.7
115200	2	20.0
230400	0	20.0

Bit Rate	UBRR	% of error
4.9152 Mhz
300	1023	0.0
600	511	0.0
1200	255	0.0
2400	127	0.0
4800	63	0.0
9600	31	0.0
14400	20	1.6
19200	15	0.0
28800	10	3.1
38400	7	0.0
57600	4	6.2
76800	3	0.0
115200	2	12.5
230400	0	25.0

Bit Rate	UBRR	% of error
5 Mhz
300	1041	0.0
600	520	0.0
1200	259	0.2
2400	129	0.2
4800	64	0.2
9600	32	1.4
14400	21	1.4
19200	15	1.7
28800	10	1.4
38400	7	1.7
57600	4	7.8
76800	3	1.7
115200	2	10.6
230400	0	26.3

Bit Rate	UBRR	% of error
5.0688 Mhz
300	1055	0.0
600	527	0.0
1200	263	0.0
2400	131	0.0
4800	65	0.0
9600	32	0.0
14400	21	0.0
19200	16	3.0
28800	10	0.0
38400	7	3.0
57600	5	9.1
76800	3	3.0
115200	2	9.1
230400	0	27.3

Bit Rate	UBRR	% of error
6.144 Mhz
300	1279	0.0
600	639	0.0
1200	319	0.0
2400	159	0.0
4800	79	0.0
9600	39	0.0
14400	26	1.2
19200	19	0.0
28800	12	2.5
38400	9	0.0
57600	6	5.0
76800	4	0.0
115200	2	10.0
230400	1	20.0

Bit Rate	UBRR	% of error
6.4 Mhz
300	1332	0.0
600	666	0.0
1200	332	0.1
2400	166	0.2
4800	82	0.4
9600	41	0.8
14400	27	0.8
19200	20	0.8
28800	13	0.8
38400	9	4.0
57600	6	0.8
76800	4	4.0
115200	2	13.6
230400	1	15.2

Bit Rate	UBRR	% of error
7.3728 Mhz
300	1535	0.0
600	767	0.0
1200	383	0.0
2400	191	0.0
4800	95	0.0
9600	47	0.0
14400	31	0.0
19200	23	0.0
28800	15	0.0
38400	11	0.0
57600	7	0.0
76800	5	0.0
115200	3	0.0
230400	1	0.0

Bit Rate	UBRR	% of error
8 Mhz
300	1666	0.0
600	832	0.0
1200	416	0.1
2400	207	0.2
4800	103	0.2
9600	51	0.2
14400	34	0.8
19200	25	0.2
28800	16	2.1
38400	12	0.2
57600	8	3.7
76800	6	7.5
115200	3	7.8
230400	1	7.8

Bit Rate	UBRR	% of error
9.216 Mhz
300	1919	0.0
600	959	0.0
1200	479	0.0
2400	239	0.0
4800	119	0.0
9600	59	0.0
14400	39	0.0
19200	29	0.0
28800	19	0.0
38400	14	0.0
57600	9	0.0
76800	7	6.7
115200	4	0.0
230400	2	20.0

Bit Rate	UBRR	% of error
10 Mhz
300	2082	0.0
600	1041	0.0
1200	520	0.0
2400	259	0.2
4800	129	0.2
9600	64	0.2
14400	42	0.9
19200	32	1.4
28800	21	1.4
38400	15	1.7
57600	10	1.4
76800	7	1.7
115200	4	7.8
230400	2	10.6

Bit Rate	UBRR	% of error
10.24 Mhz
300	2132	0.0
600	1066	0.0
1200	532	0.1
2400	266	0.1
4800	132	0.2
9600	66	0.5
14400	43	1.0
19200	32	1.0
28800	21	1.0
38400	16	2.0
57600	10	1.0
76800	7	4.0
115200	5	8.0
230400	2	8.0

Bit Rate	UBRR	% of error
11.0592 Mhz
300	2303	0.0
600	1151	0.0
1200	575	0.0
2400	287	0.0
4800	143	0.0
9600	71	0.0
14400	47	0.0
19200	35	0.0
28800	23	0.0
38400	17	0.0
57600	11	0.0
76800	8	0.0
115200	5	0.0
230400	2	0.0

Bit Rate	UBRR	% of error
12 Mhz
300	2499	0.0
600	1249	0.0
1200	624	0.0
2400	312	0.2
4800	155	0.2
9600	77	0.2
14400	51	0.2
19200	38	0.2
28800	25	0.2
38400	19	2.4
57600	12	0.2
76800	9	2.4
115200	6	7.5
230400	2	7.8

Bit Rate	UBRR	% of error
12.288 Mhz
300	2559	0.0
600	1279	0.0
1200	639	0.0
2400	319	0.0
4800	159	0.0
9600	79	0.0
14400	52	0.6
19200	39	0.0
28800	26	1.2
38400	19	0.0
57600	12	2.5
76800	9	0.0
115200	6	5.0
230400	2	10.0

Bit Rate	UBRR	% of error
12.8 Mhz
300	2666	0.0
600	1332	0.0
1200	666	0.0
2400	332	0.1
4800	166	0.2
9600	82	0.4
14400	55	0.8
19200	41	0.8
28800	27	0.8
38400	20	0.8
57600	13	0.8
76800	9	4.0
115200	6	0.8
230400	2	13.6

Bit Rate	UBRR	% of error
14.318182 Mhz
300	2982	0.0
600	1490	0.0
1200	745	0.0
2400	372	0.0
4800	185	0.2
9600	92	0.2
14400	61	0.2
19200	46	0.8
28800	30	0.2
38400	22	1.3
57600	15	3.0
76800	11	3.0
115200	7	3.0
230400	3	3.0

Bit Rate	UBRR	% of error
14.7456 Mhz
300	3071	0.0
600	1535	0.0
1200	767	0.0
2400	383	0.0
4800	191	0.0
9600	95	0.0
14400	63	0.0
19200	47	0.0
28800	31	0.0
38400	23	0.0
57600	15	0.0
76800	11	0.0
115200	7	0.0
230400	3	0.0

Bit Rate	UBRR	% of error
16 Mhz
300	3332	0.0
600	1666	0.0
1200	832	0.0
2400	416	0.1
4800	207	0.2
9600	103	0.2
14400	68	0.6
19200	51	0.2
28800	34	0.8
38400	25	0.2
57600	16	2.1
76800	12	0.2
115200	8	3.7
230400	3	7.8

Bit Rate	UBRR	% of error
16.8 Mhz
300	3499	0.0
600	1749	0.0
1200	874	0.0
2400	437	0.1
4800	218	0.1
9600	108	0.3
14400	72	0.1
19200	54	0.6
28800	35	1.3
38400	26	1.3
57600	17	1.3
76800	13	2.4
115200	8	1.3
230400	4	9.7

Bit Rate	UBRR	% of error
18.432 Mhz
300	3839	0.0
600	1919	0.0
1200	959	0.0
2400	479	0.0
4800	239	0.0
9600	119	0.0
14400	79	0.0
19200	59	0.0
28800	39	0.0
38400	29	0.0
57600	19	0.0
76800	14	0.0
115200	9	0.0
230400	4	0.0

Bit Rate	UBRR	% of error
20 Mhz
300	4166	0.0
600	2082	0.0
1200	1041	0.0
2400	520	0.0
4800	259	0.2
9600	129	0.2
14400	86	0.2
19200	64	0.2
28800	42	0.9
38400	32	1.4
57600	21	1.4
76800	15	1.7
115200	10	1.4
230400	4	7.8

Bit Rate	UBRR	% of error
30 Mhz
300	6249	0.0
600	3124	0.0
1200	1562	0.0
2400	780	0.0
4800	390	0.1
9600	194	0.2
14400	129	0.2
19200	97	0.4
28800	64	0.2
38400	48	0.4
57600	32	1.4
76800	23	1.7
115200	15	1.7
230400	7	1.7

Bit Rate	UBRR	% of error
32.768 Mhz
300	6826	0.0
600	3412	0.0
1200	1706	0.0
2400	852	0.0
4800	426	0.1
9600	212	0.2
14400	141	0.2
19200	106	0.3
28800	70	0.2
38400	52	0.6
57600	35	1.2
76800	26	1.2
115200	17	1.2
230400	8	1.2

Bit Rate	UBRR	% of error
40 Mhz
300	8332	0.0
600	4166	0.0
1200	2082	0.0
2400	1041	0.0
4800	520	0.0
9600	259	0.2
14400	173	0.2
19200	129	0.2
28800	86	0.2
38400	64	0.2
57600	42	0.9
76800	32	1.4
115200	21	1.4
230400	10	1.4

Legend:
UBRR out of range
UBRR and clock speed are a perfect match
UBRR and clock speed are less than 1% off
UBRR and clock speed are between 1% and 2% off
UBRR and clock speed are between 2% and 3% off
UBRR and clock speed are between 3% and 5% off
UBRR and clock speed is over 5% off

I call this a "baud rate calculator", however, "baud rate" is technically an incorrect term. It should be called a "bit rate calculator". Because people misuse the term "baud" so frequently, many do not know there is a difference between "bit rate" and "baud rate". I use the term "baud rate" on the title, knowing it is wrong, so people would be able to find this page, when searching the web, however, all other references are as "bit rate".

NOTE: This page was originally written when there was only one UBRR register, but newer AVR models have 2 UBRR registers, so some of the lower values that show out of range, are really in range. I will update this page some time in the future.

How to use this page:
Without entering anything, you can get a list of the UBRR settings for many popular clock speeds, and serial port bit rates. What makes this program special, is the fact that you can tell it what serial port bit rate you want, and it will tell you all the possible clock speeds that will generate your desired serial port bit rate. You can also give it a clock speed, and it will tell you all the possible serial port bit rates that can be producted with that clock speed. This is very handy when you are searching through your "junk pile", looking for the right crystal, or oscillator to generate a given serial port bit rate.
If you enter a serial port bit rate, not already listed, then the serial port bit rate will be listed as the last entry on each clock speed table. If you enter a clock speed that is not already listed, then a new clock speed table will be added to the end of the list.

If you would like to contact me about this program, if you have any questions or requests then stop by channel #avr on the FreeNode IRC network.

AVRBaudCalc is ©2005-2013 by WormFood

Bit Rate		Show table of all possible clock speeds, for a given bit rate
Clock Freq, in Mhz		Show table of all possible bit rates, for a given clock speed
		show additional double speed mode information
		show additional synchronous mode information