Cup Series
William Byron (2021)
2021 Statistics
| Driver Points | 2292 | Driver Points Rank | 5 |
| Races Won | 1 | Points per NASCAR Race | 31.5 |
| Races Won (%) | 2.8% | NASCAR Won (%) | 2.8% |
| Average Start | 8.7 | Average Finish Overall | 13.6 |
| Average Finish Last 5 | 8.2 | Average Finish Last 10 | 15.1 |
| Driver Races Run | 36 | Points per Driver Race Run | 31.5 |
| NASCAR Races Run | 36 | Percentage NASCAR Races Run | 100% |
| Top 5 Finishes | 12 | Races Top 5 (%) | 33.3% |
| Top 10 Finishes | 20 | Races Top 10 (%) | 55.6% |
| NASCAR Top 5 (%) | 33.3% | NASCAR Top 10 (%) | 55.6% |
| Avg Start-to-Finish | -4.9 | Best Start Position | 1 |
| Driver Laps Run | 8,962 | Driver Races Laps | 9,200 |
| Percentage Race Laps Run | 97.4% | Percentage Races Finished Laps Run | 99.8% |
| NASCAR Races Laps | 9,200 | Percentage NASCAR Laps Run | 97.4% |
| Did Not Finish | 5 | Did Not Finish (%) | 13.9% |
2021 Race by Race for William Byron
| Date | Event Name | Finish | Start | Laps Run | Race Laps | Pts/PP Earned | Odds | Finish Status |
| 2/9/21 | Busch Clash at DAYTONA | 5 | 5 | 35 | 35 | 0/0 | 18-1 | Running |
| 2/11/21 | Bluegreen Vacations Duel 2 at DAYTONA | 19 | 1 | 56 | 63 | 0/0 | Accident | |
| 2/14/21 | DAYTONA 500 | 26 | 2 | 191 | 200 | 11/0 | 13-1 | Running |
| 2/21/21 | O'Reilly Auto Parts 253 At DAYTONA | 33 | 22 | 69 | 70 | 8/0 | 18-1 | Running |
| 2/28/21 | Dixie Vodka 400 | 1 | 31 | 267 | 267 | 57/6 | 28-1 | Running |
| 3/7/21 | Pennzoil 400 presented by Jiffy Lube | 8 | 2 | 267 | 267 | 40/0 | 18-1 | Running |
| 3/14/21 | Instacart 500 | 8 | 10 | 312 | 312 | 36/0 | 18-1 | Running |
| 3/21/21 | Folds of Honor QuikTrip 500 | 8 | 9 | 325 | 325 | 36/0 | 16-1 | Running |
| 3/29/21 | Food City Dirt Race | 6 | 8 | 253 | 253 | 40/0 | 25-1 | Running |
| 4/10/21 | Blue-Emu Maximum Pain Relief 500 | 4 | 3 | 500 | 500 | 42/0 | 18-1 | Running |
| 4/18/21 | TOYOTA OWNERS 400 | 7 | 4 | 400 | 400 | 40/0 | 18-1 | Running |
| 4/25/21 | GEICO 500 | 2 | 4 | 191 | 191 | 41/0 | 7-1 | Running |
| 5/2/21 | Buschy McBusch Race 400 | 9 | 2 | 267 | 267 | 34/0 | 6-1 | Running |
| 5/9/21 | Goodyear 400 | 4 | 5 | 293 | 293 | 43/0 | 16-1 | Running |
| 5/16/21 | Drydene 400 | 4 | 3 | 400 | 400 | 45/0 | 16-1 | Running |
| 5/23/21 | EchoPark Texas Grand Prix | 11 | 5 | 54 | 54 | 26/0 | 18-1 | Running |
| 5/30/21 | Coca-Cola 600 | 4 | 4 | 400 | 400 | 58/0 | 16-1 | Running |
| 6/6/21 | Toyota / Save Mart 350 | 35 | 3 | 76 | 92 | 7/0 | 10-1 | Accident |
| 6/13/21 | NASCAR All-Star Race | 7 | 8 | 100 | 100 | 0/0 | 12-1 | Running |
| 6/20/21 | Ally 400 | 3 | 4 | 300 | 300 | 41/0 | 11-1 | Running |
| 6/26/21 | Pocono Organics CBD 325 | 3 | 2 | 130 | 130 | 50/0 | 9-1 | Running |
| 6/27/21 | Explore the Pocono Mountains 350 | 12 | 18 | 140 | 140 | 35/1 | 95-1 | Running |
| 7/4/21 | Jockey Made in America 250 presented by Kwik Trip | 33 | 1 | 62 | 62 | 23/1 | 18-1 | Running |
| 7/11/21 | Quaker State 400 presented by Walmart | 20 | 19 | 259 | 260 | 20/0 | 5-2 | Running |
| 7/18/21 | Foxwoods Resort Casino 301 | 21 | 16 | 292 | 293 | 16/0 | 16-1 | Running |
| 8/8/21 | Go Bowling at The Glen | 6 | 15 | 90 | 90 | 37/0 | Running | |
| 8/15/21 | Verizon 200 at the Brickyard | 33 | 1 | 77 | 95 | 4/0 | 20-1 | Accident |
| 8/22/21 | FireKeepers Casino 400 | 2 | 18 | 200 | 200 | 43/0 | 50-1 | Running |
| 8/28/21 | Coke Zero Sugar 400 | 37 | 2 | 146 | 165 | 9/0 | 25-1 | Accident |
| 9/5/21 | Cook Out Southern 500 | 34 | 14 | 199 | 367 | 3/0 | Accident | |
| 9/11/21 | Federated Auto Parts 400 Salute to First Responders | 19 | 14 | 398 | 400 | 18/0 | 16-1 | Running |
| 9/18/21 | Bass Pro Shops Night Race | 3 | 14 | 500 | 500 | 42/0 | Running | |
| 9/26/21 | South Point 400 | 18 | 3 | 266 | 267 | 25/0 | 12-1 | Running |
| 10/4/21 | YellaWood 500 | 36 | 10 | 115 | 117 | 1/0 | Accident | |
| 10/10/21 | Bank of America ROVAL 400 | 11 | 11 | 109 | 109 | 30/0 | 12-1 | Running |
| 10/17/21 | Autotrader EchoPark Automotive 500 | 2 | 12 | 334 | 334 | 50/0 | 66-1 | Running |
| 10/24/21 | Hollywood Casino 400 | 6 | 9 | 267 | 267 | 50/1 | 40-1 | Running |
| 10/31/21 | Xfinity 500 | 5 | 11 | 501 | 501 | 47/0 | 10-1 | Running |
| 11/7/21 | NASCAR Cup Series Championship | 17 | 3 | 312 | 312 | 26/0 | 16-1 | Running |