WormFood's AVR Baud Rate Calculator


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 synchronous mode information
Show additional double speed mode information (U2X=1)
Consider only 8-bit UBRR values as being valid
Hide tables except for user supplied clock rate

32.768 Khz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30060x00062.5
60020x000212.1
120010x000117.2
240000x000017.2
480000x0000134.4
960000x0000368.8
1440000x0000603.1
1920000x0000837.5
2880000x00001306.2
3840000x00001775.0
5760000x00002712.5
7680000x00003650.0
11520000x00005525.0
23040000x000011150.0
25000000x000012107.0
1.8432 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3003830x017F0.0
6001910x00BF0.0
1200950x005F0.0
2400470x002F0.0
4800230x00170.0
9600110x000B0.0
1440070x00070.0
1920050x00050.0
2880030x00030.0
3840020x00020.0
5760010x00010.0
7680010x000133.3
11520000x00000.0
23040000x0000100.0
25000000x0000117.0
2 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3004160x01A00.0
6002070x00CF0.2
12001030x00670.2
2400510x00330.2
4800250x00190.2
9600120x000C0.2
1440080x00083.7
1920060x00067.5
2880030x00037.8
3840020x00027.8
5760010x00017.8
7680010x000122.9
11520000x00007.8
23040000x000084.3
25000000x0000100.0
2.4576 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3005110x01FF0.0
6002550x00FF0.0
12001270x007F0.0
2400630x003F0.0
4800310x001F0.0
9600150x000F0.0
14400100x000A3.1
1920070x00070.0
2880040x00046.2
3840030x00030.0
5760020x000212.5
7680010x00010.0
11520000x000025.0
23040000x000050.0
25000000x000062.8
3.072 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3006390x027F0.0
6003190x013F0.0
12001590x009F0.0
2400790x004F0.0
4800390x00270.0
9600190x00130.0
14400120x000C2.5
1920090x00090.0
2880060x00065.0
3840040x00040.0
5760020x000210.0
7680020x000220.0
11520010x000120.0
23040000x000020.0
25000000x000030.2
3.2768 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3006820x02AA0.0
6003400x01540.0
12001700x00AA0.2
2400840x00540.4
4800420x002A0.8
9600200x00141.6
14400130x000D1.6
19200100x000A3.1
2880060x00061.6
3840040x00046.2
5760030x000312.5
7680020x000212.5
11520010x000112.5
23040000x000012.5
25000000x000022.1
3.579545 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3007450x02E90.0
6003720x01740.0
12001850x00B90.2
2400920x005C0.2
4800460x002E0.8
9600220x00161.3
14400150x000F3.0
19200110x000B3.0
2880070x00073.0
3840050x00053.0
5760030x00033.0
7680020x00023.0
11520010x00013.0
23040000x00003.0
25000000x000011.7
3.6864 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3007670x02FF0.0
6003830x017F0.0
12001910x00BF0.0
2400950x005F0.0
4800470x002F0.0
9600230x00170.0
14400150x000F0.0
19200110x000B0.0
2880070x00070.0
3840050x00050.0
5760030x00030.0
7680020x00020.0
11520010x00010.0
23040000x00000.0
25000000x00008.5
3.93216 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3008180x03320.0
6004090x01990.0
12002040x00CC0.0
24001010x00650.4
4800500x00320.4
9600250x00191.6
14400160x00100.4
19200120x000C1.6
2880080x00085.5
3840050x00056.2
5760030x00036.2
7680020x00026.2
11520010x00016.2
23040000x00006.2
25000000x00001.7
4 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3008320x03400.0
6004160x01A00.0
12002070x00CF0.2
24001030x00670.2
4800510x00330.2
9600250x00190.2
14400160x00102.1
19200120x000C0.2
2880080x00083.7
3840060x00067.5
5760030x00037.8
7680020x00027.8
11520010x00017.8
23040000x00007.8
25000000x00000.0
4.194304 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3008730x03690.0
6004360x01B40.0
12002170x00D90.2
24001080x006C0.2
4800540x00360.7
9600260x001A1.1
14400170x00111.1
19200130x000D2.5
2880080x00081.1
3840060x00062.5
5760040x00049.9
7680020x000212.1
11520010x000112.1
23040000x000012.1
25000000x00004.6
4.433619 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3009230x039B0.0
6004610x01CD0.0
12002300x00E60.0
24001140x00720.4
4800570x00390.5
9600280x001C0.5
14400180x00121.3
19200130x000D3.0
2880090x00093.9
3840060x00063.0
5760040x00043.9
7680030x000310.9
11520010x000116.9
23040000x000016.9
25000000x00009.8
4.608 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
3009590x03BF0.0
6004790x01DF0.0
12002390x00EF0.0
24001190x00770.0
4800590x003B0.0
9600290x001D0.0
14400190x00130.0
19200140x000E0.0
2880090x00090.0
3840070x00076.7
5760040x00040.0
7680030x00036.7
11520020x000220.0
23040000x000020.0
25000000x000013.2
4.9152 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30010230x03FF0.0
6005110x01FF0.0
12002550x00FF0.0
24001270x007F0.0
4800630x003F0.0
9600310x001F0.0
14400200x00141.6
19200150x000F0.0
28800100x000A3.1
3840070x00070.0
5760040x00046.2
7680030x00030.0
11520020x000212.5
23040000x000025.0
25000000x000018.6
5 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30010410x04110.0
6005200x02080.0
12002590x01030.2
24001290x00810.2
4800640x00400.2
9600320x00201.4
14400210x00151.4
19200150x000F1.7
28800100x000A1.4
3840070x00071.7
5760040x00047.8
7680030x00031.7
11520020x000210.6
23040000x000026.3
25000000x000020.0
5.0688 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30010550x041F0.0
6005270x020F0.0
12002630x01070.0
24001310x00830.0
4800650x00410.0
9600320x00200.0
14400210x00150.0
19200160x00103.0
28800100x000A0.0
3840070x00073.0
5760050x00059.1
7680030x00033.0
11520020x00029.1
23040000x000027.3
25000000x000021.1
6.144 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30012790x04FF0.0
6006390x027F0.0
12003190x013F0.0
24001590x009F0.0
4800790x004F0.0
9600390x00270.0
14400260x001A1.2
19200190x00130.0
28800120x000C2.5
3840090x00090.0
5760060x00065.0
7680040x00040.0
11520020x000210.0
23040010x000120.0
25000010x000130.2
6.4 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30013320x05340.0
6006660x029A0.0
12003320x014C0.1
24001660x00A60.2
4800820x00520.4
9600410x00290.8
14400270x001B0.8
19200200x00140.8
28800130x000D0.8
3840090x00094.0
5760060x00060.8
7680040x00044.0
11520020x000213.6
23040010x000115.2
25000010x000125.0
7.3728 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30015350x05FF0.0
6007670x02FF0.0
12003830x017F0.0
24001910x00BF0.0
4800950x005F0.0
9600470x002F0.0
14400310x001F0.0
19200230x00170.0
28800150x000F0.0
38400110x000B0.0
5760070x00070.0
7680050x00050.0
11520030x00030.0
23040010x00010.0
25000010x00018.5
8 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30016660x06820.0
6008320x03400.0
12004160x01A00.0
24002070x00CF0.2
48001030x00670.2
9600510x00330.2
14400340x00220.8
19200250x00190.2
28800160x00102.1
38400120x000C0.2
5760080x00083.7
7680060x00067.5
11520030x00037.8
23040010x00017.8
25000010x00010.0
9.216 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30019190x077F0.0
6009590x03BF0.0
12004790x01DF0.0
24002390x00EF0.0
48001190x00770.0
9600590x003B0.0
14400390x00270.0
19200290x001D0.0
28800190x00130.0
38400140x000E0.0
5760090x00090.0
7680070x00076.7
11520040x00040.0
23040020x000220.0
25000010x000113.2
10 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30020820x08220.0
60010410x04110.0
12005200x02080.0
24002590x01030.2
48001290x00810.2
9600640x00400.2
14400420x002A0.9
19200320x00201.4
28800210x00151.4
38400150x000F1.7
57600100x000A1.4
7680070x00071.7
11520040x00047.8
23040020x000210.6
25000020x000220.0
10.24 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30021320x08540.0
60010660x042A0.0
12005320x02140.0
24002660x010A0.1
48001320x00840.2
9600660x00420.5
14400430x002B1.0
19200320x00201.0
28800210x00151.0
38400160x00102.0
57600100x000A1.0
7680070x00074.0
11520050x00058.0
23040020x00028.0
25000020x000217.2
11.0592 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30023030x08FF0.0
60011510x047F0.0
12005750x023F0.0
24002870x011F0.0
48001430x008F0.0
9600710x00470.0
14400470x002F0.0
19200350x00230.0
28800230x00170.0
38400170x00110.0
57600110x000B0.0
7680080x00080.0
11520050x00050.0
23040020x00020.0
25000020x00028.5
12 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30024990x09C30.0
60012490x04E10.0
12006240x02700.0
24003120x01380.2
48001550x009B0.2
9600770x004D0.2
14400510x00330.2
19200380x00260.2
28800250x00190.2
38400190x00132.4
57600120x000C0.2
7680090x00092.4
11520060x00067.5
23040020x00027.8
25000020x00020.0
12.288 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30025590x09FF0.0
60012790x04FF0.0
12006390x027F0.0
24003190x013F0.0
48001590x009F0.0
9600790x004F0.0
14400520x00340.6
19200390x00270.0
28800260x001A1.2
38400190x00130.0
57600120x000C2.5
7680090x00090.0
11520060x00065.0
23040020x000210.0
25000020x00022.3
12.8 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30026660x0A6A0.0
60013320x05340.0
12006660x029A0.0
24003320x014C0.1
48001660x00A60.2
9600820x00520.4
14400550x00370.8
19200410x00290.8
28800270x001B0.8
38400200x00140.8
57600130x000D0.8
7680090x00094.0
11520060x00060.8
23040020x000213.6
25000020x00026.3
14.318182 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30029820x0BA60.0
60014900x05D20.0
12007450x02E90.0
24003720x01740.0
48001850x00B90.2
9600920x005C0.2
14400610x003D0.2
19200460x002E0.8
28800300x001E0.2
38400220x00161.3
57600150x000F3.0
76800110x000B3.0
11520070x00073.0
23040030x00033.0
25000030x000311.7
14.7456 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30030710x0BFF0.0
60015350x05FF0.0
12007670x02FF0.0
24003830x017F0.0
48001910x00BF0.0
9600950x005F0.0
14400630x003F0.0
19200470x002F0.0
28800310x001F0.0
38400230x00170.0
57600150x000F0.0
76800110x000B0.0
11520070x00070.0
23040030x00030.0
25000030x00038.5
16 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30033320x0D040.0
60016660x06820.0
12008320x03400.0
24004160x01A00.0
48002070x00CF0.2
96001030x00670.2
14400680x00440.6
19200510x00330.2
28800340x00220.8
38400250x00190.2
57600160x00102.1
76800120x000C0.2
11520080x00083.7
23040030x00037.8
25000030x00030.0
16.8 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30034990x0DAB0.0
60017490x06D50.0
12008740x036A0.0
24004370x01B50.1
48002180x00DA0.1
96001080x006C0.3
14400720x00480.1
19200540x00360.6
28800350x00231.3
38400260x001A1.3
57600170x00111.3
76800130x000D2.4
11520080x00081.3
23040040x00049.7
25000030x00034.8
17.664 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30036790x0E5F0.0
60018390x072F0.0
12009190x03970.0
24004590x01CB0.0
48002290x00E50.0
96001140x00720.0
14400760x004C0.4
19200570x00390.9
28800370x00250.9
38400280x001C0.9
57600180x00120.9
76800130x000D2.6
11520090x00094.3
23040040x00044.3
25000030x00039.4
18.432 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30038390x0EFF0.0
60019190x077F0.0
12009590x03BF0.0
24004790x01DF0.0
48002390x00EF0.0
96001190x00770.0
14400790x004F0.0
19200590x003B0.0
28800390x00270.0
38400290x001D0.0
57600190x00130.0
76800140x000E0.0
11520090x00090.0
23040040x00040.0
25000040x00048.5
20 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30041660x10460.0
60020820x08220.0
120010410x04110.0
24005200x02080.0
48002590x01030.2
96001290x00810.2
14400860x00560.2
19200640x00400.2
28800420x002A0.9
38400320x00201.4
57600210x00151.4
76800150x000F1.7
115200100x000A1.4
23040040x00047.8
25000040x00040.0
30 Mhz
Baud RateUBRR
(dec)
UBRR
(hex)
% of
error
30062490x18690.0
60031240x0C340.0
120015620x061A0.0
24007800x030C0.0
48003900x01860.0
96001940x00C20.2
144001290x00810.2
19200970x00610.4
28800640x00400.2
38400480x00300.4
57600320x00201.4
76800230x00171.7
115200150x000F1.7
23040070x00071.7
25000070x00076.7
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 about the UBRR register(s): Some AVRs only have a single UBRR register, while other AVRs have two UBRR registers. If your AVR has only 1 UBRR register, then you can check the box "Consider only 8-bit UBRR values as being valid" to have it show you when the UBRR value is out of range for your AVR. If your AVR handles a 12-bit UBRR value, then the UBRR value in hexadecimal will be helpful to you, because it will make it easier to find the UBRRH and UBRRL values (I'm sure you can figure out what goes where).

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 generated as the first table, with your clock speed.


If you notice any errors, please, please, please report them to me. 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