The national parties allocate each state a certain number of delegates based on complex formulas that take into account how many electoral votes the state has, how many party members are in that state's congressional delegation, and other factors. Generally, you get bonus delegates for doing well in your state. Some delegates are chosen by (congressional or state senate) district, some are chosen statewide at large, and some are ex officio delegates by virtue of being a governor, senator, member of the DNC or RNC, or holder of some important office. The party leaders and elected officials who are automatically delegates are called PLEOs. Both parties have both pledged delegates (people who have promised to vote for a certain candidate on the first ballot) and unpledged delegates (who can vote their heart on every ballot).

For the ultimate political junkie, heaven is studying the actual rules for how the delegates are allocated. For the Democrats here are the rules. For the Republicans here are the rules. If you want to get down into the weeds, they are rather complicated, and the allocation can yet change, for example, if a party wins or loses an office in a special election before the convention. Here is the allocation as it stands now.

It is important to note that the Democrats have a much bigger convention than the Republicans do, with 4483 delegates vs. 2470. The number of people on the convention floor may be even larger, since some states have half, third, or quarter delegates. There are also alternates present, in case something happens to one or more delegates.

Republicans							Democrats
State	District	At large	PLEO	Bonus	Total		State	District	At large	PLEO	Supers	Total
Alabama	21	10	3	16	50		Alabama	34	11	7	6	58
Alaska	3	10	3	12	28		Alaska	9	3	2	4	18
Amer. Samoa		6	3		9		Amer. Samoa		6		4	10
Arizona	27	10	3	18	58		Arizona	41	14	8	12	75
Arkansas	12	10	3	15	40		Arkansas	21	7	4	5	37
California	159	10	3		172		California	264	88	53	71	476
Colorado	21	10	3	3	37		Colorado	42	14	8	13	77
Connecticut	15	10	3		28		Connecticut	33	11	7	14	65
Delaware	3	10	3		16		Delaware	11	4	2	10	27
DC		16	3		19		DC	11	4	2	20	37
Florida	81	10	3	5	99		Florida	135	45	27	31	238
Georgia	42	10	3	21	76		Georgia	64	21	13	14	112
Guam		6	3		9		Guam		6		5	11
Hawaii	6	10	3		19		Hawaii	14	5	3	9	31
Idaho	6	10	3	13	32		Idaho	13	4	3	4	24
Illinois	54	10	3	2	69		Illinois	104	35	21	30	190
Indiana	27	10	3	17	57		Indiana	46	15	9	9	79
Iowa	12	10	3	5	30		Iowa	30	10	6	8	54
Kansas	12	10	3	15	40		Kansas	22	7	4	4	37
Kentucky	18	10	3	14	45		Kentucky	31	10	6	6	53
Louisiana	18	10	3	15	46		Louisiana	35	12	7	7	61
Maine	6	10	3	4	23		Maine	17	5	3	5	30
Maryland	24	10	3	1	38		Maryland	51	17	10	27	105
Massachusetts	27	10	3	2	42		Massachusetts	62	21	12	26	121
Michigan	42	10	3	4	59		Michigan	87	29	17	19	152
Minnesota	24	10	3	1	38		Minnesota	51	17	10	16	94
Mississippi	12	10	3	14	39		Mississippi	23	8	5	5	41
Missouri	24	10	3	15	52		Missouri	49	16	10	13	88
Montana	3	10	3	11	27		Montana	10	3	2	7	22
Nebraska	9	10	3	14	36		Nebraska	17	6	3	5	31
Nevada	12	10	3	5	30		Nevada	20	7	4	8	39
New Hampshire	6	10	3	4	23		New Hampshire	16	5	3	8	32
New Jersey	36	10	3	2	51		New Jersey	72	24	14	16	126
New Mexico	9	10	3	2	24		New Mexico	19	6	4	9	38
New York	81	10	3	1	95		New York	152	51	30	44	277
North Carolina	39	10	3	20	72		North Carolina	70	23	14	13	120
North Dakota	3	10	3	12	28		North Dakota	9	3	2	5	19
N. Marianas		6	3		9		N. Marianas		6		5	11
Ohio	48	10	3	5	66		Ohio	97	32	19	17	165
Oklahoma	15	10	3	15	43		Oklahoma	25	8	5	4	42
Oregon	15	10	3		28		Oregon	34	11	7	12	64
Pennsylvania	54	10	3	4	71		Pennsylvania	104	35	21	21	181
Puerto Rico		20	3		23		Puerto Rico	33	11	7	7	58
Rhode Island	6	10	3		19		Rhode Island	14	5	3	9	31
South Carolina	21	10	3	16	50		South Carolina	33	11	7	6	57
South Dakota	3	10	3	13	29		South Dakota	10	3	2	5	20
Tennessee	27	10	3	18	58		Tennessee	44	15	9	9	77
Texas	108	10	3	34	155		Texas	136	45	27	29	237
Utah	12	10	3	15	40		Utah	16	5	3	4	28
Vermont	3	10	3		16		Vermont	10	3	2	8	23
Virgin Islands		6	3		9		Virgin Islands		6		5	11
Virginia	33	10	3	3	49		Virginia	62	21	12	17	112
Washington	30	10	3	1	44		Washington	56	19	11	16	102
West Virginia	9	10	3	12	34		West Virginia	17	6	3	9	35
Wisconsin	24	10	3	5	42		Wisconsin	52	17	10	10	89
Wyoming	3	10	3	13	29		Wyoming	8	3	2	4	17
Totals	1305	560	168	437	2470		Democrats Abroad		12	1	4	17
							Unassigned				1	1
							Totals	2436	847	486	714	4483

Democrats Abroad is part of the Democratic Party and gets delegates just like states do. Republicans Abroad is not part of the
Republican Party and gets no delegates. However, since it is not part of the Republican Party, it is free to take unlimited donations
from foreigners, something Democrats Abroad is forbidden from doing.

District = delegates chosen by district
At large = delegates chosen statewide
PLEO = Party Leaders and Elected Officials
Bonus = extra delgates given to Republican states good at electing Republicans
Supers = Democratic superdelegates