√128 ≈ 11.3137
√128 is an irrational number, so its decimals never end or repeat. It sits between 11 and 12 because 11² = 121 and 12² = 144.
| Decimal places | Value |
|---|---|
| 0 | 11 |
| 1 | 11.3 |
| 2 | 11.31 |
| 3 | 11.314 |
| 4 | 11.3137 |
| 5 | 11.31371 |
| 10 (digits) | 11.3137084990 |
128 = 64 × 2 and √64 = 8, so √128 = 8√2.
11.3137 × 11.3137 ≈ 127.9998, which is very close to 128.
Need another number? Use the square root calculator (also cube roots and other roots).
| Number | Square root |
|---|---|
| 124 | 11.1355 |
| 125 | 11.1803 |
| 126 | 11.2250 |
| 127 | 11.2694 |
| 129 | 11.3578 |
| 130 | 11.4018 |
| 131 | 11.4455 |
| 132 | 11.4891 |