Experience required for Gaining Levels

Specialists: Fighter, Rogue, Bard, Gadgeteer 
Specialist Casters: Priest, Mage, Psionic, Alchemist
Hybrids: Lord, Valkyrie, Ranger, Samurai, Monk 
Elites: Ninja, Bishop

Each class begins the game at level 1 unless the party was imported from Wizardry 7, then they may advance as far as level 5.
Level
Specialists
Specialist Casters
Hybrids
Elites
2
 1,000 1,200 1,400 1,600
3
 2,000 2,400 2,800 3,200
4
 4,000 4,800 5,600 6,400
5
 8,000 9,600 11,200 12,800
6
 16,000 19,200 22,400 25,600
7
 32,000 38,400 44,800 51,200
8
 64,000 76,800 89,600 102,400
9
 128,000 153,600 179,200 204,800
10
 256,000 307,200 358,400 409,600
11
 512,000 614,400 716,800 819,200
12
 819,200 983,040 1,146,880 1,310,720
13
 1,187,840 1,425,408 1,662,976 1,900,544
14
 1,630,208 1,956,249 2,282,291 2,608,332
15
 2,161,049 2,593,258 3,025,469 3,457,677
16
 2,798,058 3,357,668 3,917,282 4,476,891
17
 3,562,468 4,274,960 4,987,457 5,699,947
18
 4,479,760 5,375,710 6,271,667 7,167,614
19
 5,580,510 6,696,610 7,812,719 8,928,814
20
 6,901,410 8,281,690 9,661,981 11,042,254
21
 8,486,490 10,183,786 11,881,095 13,578,382
22
 10,388,586 12,466,301 14,544,031 16,621,735
23
 12,671,101 15,205,319 17,739,554 20,273,758
24
 15,410,119 18,492,140 21,574,181 24,656,185
25
 18,696,940 22,436,325 26,175,733 29,915,097
26
 22,641,125 27,169,347 31,697,595 36,225,791
27
 27,374,147 32,848,973 38,323,829 43,798,623
28
 33,053,773 39,664,524 46,275,309 52,886,021
29
 39,869,324 47,843,185 55,817,085 63,790,898
30
 48,047,985 57,657,578 67,267,216 76,876,750
31
 57,862,378 69,434,849 81,007,373 92,579,772
32
 69,639,649 83,567,574 97,495,561 111,423,398
33
 83,772,374 100,526,844 117,281,386 134,035,749
34
 100,731,644 120,877,968 141,024,376 161,170,570
35
 121,082,768 145,299,316 169,515,964 193,732,355
36
 145,504,116 174,604,933 203,705,869 232,806,497
37
 174,809,733 209,771,673 244,733,755 279,695,467
38
 209,976,473 251,971,761 293,967,218 335,962,231
39
 252,176,561 302,611,866 353,047,373 403,482,347
40
 302,816,666 363,379,992 423,943,559 484,506,486
41
 363,584,792 436,301,743 509,018,982 581,735,452
42
 436,506,543 523,807,844 611,109,489 698,410,211
43
 524,012,644 628,815,165 733,618,097 838,419,921
44
 629,019,965 754,823,950 880,628,426 1,006,431,573
45
 755,028,750 906,034,492 1,057,040,820 1,208,045,555
46
 906,239,292 1,087,487,142 1,268,735,692 1,449,982,333
47
 1,087,691,942 1,305,230,322 1,522,769,538 1,740,306,466
48
 1,305,435,122 1,566,522,138 1,827,610,153 2,088,695,425
49
 1,566,726,938 1,880,072,317 2,193,418,891 2,506,762,175
50
 1,880,277,117 2,256,332,531 2,202,892,647 2,578,945,545