Hi Shekhar,

JEE Main marks vs percentile of April or May session is mentioned below:-

• -75 - -20: 0.843517743614459 - 0.843517743614459 percentile
• -19 - -10: 0.843517743614459 - 0.843517743614459 percentile
• 0 - 10: 0.843517743614459 - 9.69540662201048 percentile
• 11 - 20: 13.4958497103427 - 33.2291283360524 percentile
• 21 - 30: 37.6945295632834 - 56.5693109770195 percentile
• 31 - 40: 58.1514901857346 - 71.3020522957121 percentile
• 41 - 50: 73.2878087751462 - 80.9821538087469 percentile
• 51 - 60: 82.0160627661434 - 86.9079446541208 percentile
• 61 - 70: 87.5122250914779 - 90.7022005707394 percentile
• 71 - 80: 91.0721283110867 - 93.1529718505396 percentile
• 81 - 90: 93.4712312797351 - 94.7494792463808 percentile
• 91 - 100: 94.9985943180054 - 96.0648502433078 percentile
• 101 - 110: 96.2045500677875 - 96.9782721725982 percentile
• 111 - 120: 97.1429377776765 - 97.6856721385145 percentile
• 121 - 130: 97.8112608696124 - 98.2541321080562 percentile
• 131 - 140: 98.3174149345299 - 98.6669358629096 percentile
• 141 - 150: 98.7323896268267 - 98.9902969950969 percentile
• 151 - 160: 99.0286140409721 - 99.2397377073381 percentile
• 161 - 170: 99.272084675244 - 99.4312143898418 percentile
• 171 - 180: 99.4569399985455 - 99.573193698637 percentile
• 181 - 190: 99.5973996511304 - 99.6885790237511 percentile
• 191 - 200: 99.7108311325455 - 99.7824720681761 percentile
• 201 - 210: 99.7950635053476 - 99.845212160289 percentile
• 211 - 220: 99.8516164257469 - 99.8937326121479 percentile
• 221 - 230: 99.9011137994553 - 99.9289017987302 percentile
• 231 - 240: 99.9349804235716 - 99.9563641573886 percentile
• 241 - 250: 99.9601632979145 - 99.9750342194015 percentile
• 250 - 262: 99.9772051568448 - 99.9888196721667 percentile
• 263 - 270: 99.9909906096101 - 99.9940299220308 percentile
• 271 - 280: 99.9946812032638 - 99.997394875068 percentile
• 300: 99.99989145 percentile

Refer here for more info - JEE Main 2021 Marks vs Percentile vs Rank – Calculate Marks using percentile score (careers360.com)

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck!