| Ships | Tonnage | U-Boat Losses | |
| 1939 | 95 | 417,421 | 9 |
| September | 29 | 152,040 | 2 |
| October | 21 | 104,712 | 5 |
| November | 22 | 57,173 | 1 |
| December | 23 | 103,496 | 1 |
| 1940 | 822 | 3,465,573 | 24 |
| January | 24 | 101,869 | 1 |
| February | 21 | 110,374 | 6 |
| March | 13 | 39,302 | 2 |
| April | 19 | 74,838 | 5 |
| May | 77 | 273,219 | 1 |
| June | 125 | 471,496 | 2 |
| July | 98 | 381,967 | 1 |
| August | 88 | 394,010 | 2 |
| September | 90 | 442,634 | 1 |
| October | 97 | 442,452 | 1 |
| November | 91 | 376,098 | 2 |
| December | 79 | 357,314 | - |
| 1941 | 1,141 | 4,190,281 | 34 |
| January | 75 | 320,048 | - |
| February | 100 | 401,768 | - |
| March | 139 | 537,493 | 5 |
| April | 154 | 653,960 | 2 |
| May | 126 | 500,063 | 1 |
| June | 108 | 431,037 | 4 |
| July | 43 | 120,975 | - |
| August | 41 | 130,699 | 3 |
| September | 83 | 285,752 | 2 |
| October | 51 | 218,289 | 2 |
| November | 34 | 104,212 | 5 |
| December | 187 | 485,985 | 10 |
| 1942 | 1,570 | 7,697,905 | 86 |
| January | 97 | 415,741 | 3 |
| February | 130 | 652,516 | 2 |
| March | 225 | 794,689 | 6 |
| April | 127 | 666,814 | 3 |
| May | 149 | 704,673 | 4 |
| June | 170 | 823,656 | 3 |
| July | 127 | 613,641 | 11 |
| August | 124 | 665,633 | 9 |
| September | 114 | 567,327 | 11 |
| October | 100 | 632,720 | 16 |
| November | 135 | 812,867 | 13 |
| December | 72 | 347,628 | 5 |
| 1943 | 597 | 3,220,137 | 237 |
| January | 50 | 261,359 | 6 |
| February | 73 | 403,062 | 19 |
| March | 120 | 693,389 | 17 |
| April | 64 | 344,680 | 15 |
| May | 58 | 299,428 | 40 |
| June | 28 | 123,825 | 17 |
| July | 61 | 365,398 | 37 |
| August | 25 | 119,801 | 25 |
| September | 29 | 156,419 | 9 |
| October | 29 | 139,861 | 26 |
| November | 29 | 144,391 | 19 |
| December | 31 | 168,524 | 7 |
| 1944 | 205 | 1,045,629 | 238 |
| January | 26 | 130,635 | 15 |
| February | 23 | 116,855 | 20 |
| March | 25 | 157,960 | 22 |
| April | 13 | 82,372 | 23 |
| May | 5 | 27,297 | 23 |
| June | 26 | 104,084 | 26 |
| July | 17 | 78,756 | 23 |
| August | 23 | 118,304 | 32 |
| September | 8 | 44,805 | 22 |
| October | 4 | 11,668 | 13 |
| November | 9 | 37,980 | 5 |
| December | 26 | 134,913 | 14 |
| 1945 | 105 | 438,821 | 123 |
| January | 18 | 82,897 | 8 |
| February | 26 | 95,316 | 20 |
| March | 27 | 111,204 | 25 |
| April | 22 | 104,512 | 41 |
| May | 4 | 17,198 | 29 |
| June | 2 | 18,615 | - |
| July | 3 | 7,237 | - |
| August | 1 | 36 | - |
| Not Known | 2 | 1,806 | - |
| TOTAL | 4,535 | 20,475,767 | 751 |
Notes:
(1) From September 1939 to April 1940 only British losses
(2) Includes losses from all causes in all theaters
Source: Winston Churchill, The Second World War. U-Boat losses - uboat.net.