| fermtometer | 1 fm | 2 fm | 3 fm | 4 fm | 5 fm | 6 fm | 7 fm | 8 fm | 9 fm | 10 fm | 11 fm | 12 fm | 13 fm | 14 fm | 15 fm | 16 fm | 17 fm | 18 fm | 19 fm | 20 fm | 21 fm | 22 fm | 23 fm | 24 fm | 25 fm | 26 fm | 27 fm | 28 fm | 29 fm | 30 fm | 31 fm | 32 fm | 33 fm | 34 fm | 35 fm | 36 fm | 37 fm | 38 fm | 39 fm | 40 fm | 41 fm | 42 fm | 43 fm | 44 fm | 45 fm | 46 fm | 47 fm | 48 fm | 49 fm | 50 fm | 51 fm | 52 fm | 53 fm | 54 fm | 55 fm | 56 fm | 57 fm | 58 fm | 59 fm | 60 fm | 61 fm | 62 fm | 63 fm | 64 fm | 65 fm | 66 fm | 67 fm | 68 fm | 69 fm | 70 fm | 71 fm | 72 fm | 73 fm | 74 fm | 75 fm | 76 fm | 77 fm | 78 fm | 79 fm | 80 fm | 81 fm | 82 fm | 83 fm | 84 fm | 85 fm | 86 fm | 87 fm | 88 fm | 89 fm | 90 fm | 91 fm | 92 fm | 93 fm | 94 fm | 95 fm | 96 fm | 97 fm | 98 fm | 99 fm | 100 fm |
| span | 4.3744531933508 × 10-15 span | 8.7489063867017 × 10-15 span | 1.3123359580052 × 10-14 span | 1.7497812773403 × 10-14 span | 2.1872265966754 × 10-14 span | 2.6246719160105 × 10-14 span | 3.0621172353456 × 10-14 span | 3.4995625546807 × 10-14 span | 3.9370078740157 × 10-14 span | 4.3744531933508 × 10-14 span | 4.8118985126859 × 10-14 span | 5.249343832021 × 10-14 span | 5.6867891513561 × 10-14 span | 6.1242344706912 × 10-14 span | 6.5616797900262 × 10-14 span | 6.9991251093613 × 10-14 span | 7.4365704286964 × 10-14 span | 7.8740157480315 × 10-14 span | 8.3114610673666 × 10-14 span | 8.7489063867017 × 10-14 span | 9.1863517060367 × 10-14 span | 9.6237970253718 × 10-14 span | 1.0061242344707 × 10-13 span | 1.0498687664042 × 10-13 span | 1.0936132983377 × 10-13 span | 1.1373578302712 × 10-13 span | 1.1811023622047 × 10-13 span | 1.2248468941382 × 10-13 span | 1.2685914260717 × 10-13 span | 1.3123359580052 × 10-13 span | 1.3560804899388 × 10-13 span | 1.3998250218723 × 10-13 span | 1.4435695538058 × 10-13 span | 1.4873140857393 × 10-13 span | 1.5310586176728 × 10-13 span | 1.5748031496063 × 10-13 span | 1.6185476815398 × 10-13 span | 1.6622922134733 × 10-13 span | 1.7060367454068 × 10-13 span | 1.7497812773403 × 10-13 span | 1.7935258092738 × 10-13 span | 1.8372703412073 × 10-13 span | 1.8810148731409 × 10-13 span | 1.9247594050744 × 10-13 span | 1.9685039370079 × 10-13 span | 2.0122484689414 × 10-13 span | 2.0559930008749 × 10-13 span | 2.0997375328084 × 10-13 span | 2.1434820647419 × 10-13 span | 2.1872265966754 × 10-13 span | 2.2309711286089 × 10-13 span | 2.2747156605424 × 10-13 span | 2.3184601924759 × 10-13 span | 2.3622047244094 × 10-13 span | 2.405949256343 × 10-13 span | 2.4496937882765 × 10-13 span | 2.49343832021 × 10-13 span | 2.5371828521435 × 10-13 span | 2.580927384077 × 10-13 span | 2.6246719160105 × 10-13 span | 2.668416447944 × 10-13 span | 2.7121609798775 × 10-13 span | 2.755905511811 × 10-13 span | 2.7996500437445 × 10-13 span | 2.843394575678 × 10-13 span | 2.8871391076115 × 10-13 span | 2.9308836395451 × 10-13 span | 2.9746281714786 × 10-13 span | 3.0183727034121 × 10-13 span | 3.0621172353456 × 10-13 span | 3.1058617672791 × 10-13 span | 3.1496062992126 × 10-13 span | 3.1933508311461 × 10-13 span | 3.2370953630796 × 10-13 span | 3.2808398950131 × 10-13 span | 3.3245844269466 × 10-13 span | 3.3683289588801 × 10-13 span | 3.4120734908136 × 10-13 span | 3.4558180227472 × 10-13 span | 3.4995625546807 × 10-13 span | 3.5433070866142 × 10-13 span | 3.5870516185477 × 10-13 span | 3.6307961504812 × 10-13 span | 3.6745406824147 × 10-13 span | 3.7182852143482 × 10-13 span | 3.7620297462817 × 10-13 span | 3.8057742782152 × 10-13 span | 3.8495188101487 × 10-13 span | 3.8932633420822 × 10-13 span | 3.9370078740157 × 10-13 span | 3.9807524059493 × 10-13 span | 4.0244969378828 × 10-13 span | 4.0682414698163 × 10-13 span | 4.1119860017498 × 10-13 span | 4.1557305336833 × 10-13 span | 4.1994750656168 × 10-13 span | 4.2432195975503 × 10-13 span | 4.2869641294838 × 10-13 span | 4.3307086614173 × 10-13 span | 4.3744531933508 × 10-13 span |
The femtometre (American spelling femtometer, symbol fm derived from the Danish and Norwegian word femten, "fifteen"+Ancient Greek: μέτρον, metrοn, "unit of measurement") is an SI unit of length equal to 10−15 metres, which means a quadrillionth of one. This distance can also be called a fermi and was so named in honour of physicist Enrico Fermi, as it is a typical length-scale of nuclear physics.
| 1 fermtometers = 4.3744531933508E-15 spans | 4 fermtometers = 1.7497812773403E-14 spans |
| 1.5 fermtometers = 6.5616797900262E-15 spans | 4.5 fermtometers = 1.9685039370079E-14 spans |
| 2 fermtometers = 8.7489063867017E-15 spans | 5 fermtometers = 2.1872265966754E-14 spans |
| 2.5 fermtometers = 1.0936132983377E-14 spans | 5.5 fermtometers = 2.405949256343E-14 spans |
| 3 fermtometers = 1.3123359580052E-14 spans | 6 fermtometers = 2.6246719160105E-14 spans |
A span is the distance measured by a human hand, from the tip of the thumb to the tip of the little finger. In ancient times, a span was considered to be half a cubit. Sometimes the distinction is made between the great span (thumb to little finger) and little span (index finger to little finger).
| 1 spans = 2.286E+14 fermtometers | 4 spans = 9.144E+14 fermtometers |
| 1.5 spans = 3.429E+14 fermtometers | 4.5 spans = 1.0287E+15 fermtometers |
| 2 spans = 4.572E+14 fermtometers | 5 spans = 1.143E+15 fermtometers |
| 2.5 spans = 5.715E+14 fermtometers | 5.5 spans = 1.2573E+15 fermtometers |
| 3 spans = 6.858E+14 fermtometers | 6 spans = 1.3716E+15 fermtometers |
| 1 fermtometers = 4.3744531933508 × 10-15 spans |
| 1 spans = 2.286 × 1014 fermtometers |