---
title: "BIP39 Words Starting with U — 35 Mnemonic Seed Phrase Words"
url: "https://bip39-phrase.com/bip39-words/u/"
language: "en"
updated: "2026-10-19T00:00:00+00:00"
---

# BIP39 Words Starting with U (35 words)

The 35 BIP39 words that start with U run from #1889 [ugly](/bip39-word/ugly/) to #1923 [utility](/bip39-word/utility/) in the English wordlist: indexes 1888 to 1922, or **11101100000** to **11110000010** in binary. That is 1.7% of the 2048 words, the 20th-largest of the 25 letter groups. Word length goes from 3 letters ([use](/bip39-word/use/)) to 8 ([umbrella](/bip39-word/umbrella/) and [universe](/bip39-word/universe/)).

Six three-letter beginnings are shared by two or more words; the largest, with 4 words each, are **"uni"** and **"use"**. The 16 words in these groups need their first four letters to be told apart, while 16 are identified by the first three, and 3 ([ugly](/bip39-word/ugly/), [umbrella](/bip39-word/umbrella/) and [utility](/bip39-word/utility/)) by the first two. The short word [use](/bip39-word/use/) also begins longer ones, so a four-letter backup keeps it whole.

Four of the 35 words have look-alikes one letter away, such as [use](/bip39-word/use/) and [used](/bip39-word/used/). Read aloud, 14 pairs differ by a single sound, for example [under](/bip39-word/under/) and [undo](/bip39-word/undo/). Two spellings are shared with the [French BIP39 list](/french/), at different indexes: [unique](/bip39-word/unique/) and [usage](/bip39-word/usage/). Five of the words appear in the official BIP39 test vectors, among them [uncle](/bip39-word/uncle/) and [unfold](/bip39-word/unfold/).

## All 35 BIP39 words starting with U

| #    | Word                              | Binary      | IPA            | Prefix |
| ---- | --------------------------------- | ----------- | -------------- | ------ |
| 1889 | [ugly](/bip39-word/ugly/)         | 11101100000 | /ˈʌgli/        | ugly   |
| 1890 | [umbrella](/bip39-word/umbrella/) | 11101100001 | /ʌmˈbrɛlə/     | umbr   |
| 1891 | [unable](/bip39-word/unable/)     | 11101100010 | /ʌnˈeɪbl/      | unab   |
| 1892 | [unaware](/bip39-word/unaware/)   | 11101100011 | /ˌʌnəˈweə/     | unaw   |
| 1893 | [uncle](/bip39-word/uncle/)       | 11101100100 | /ˈʌŋkl/        | uncl   |
| 1894 | [uncover](/bip39-word/uncover/)   | 11101100101 | /ʌnˈkʌvə/      | unco   |
| 1895 | [under](/bip39-word/under/)       | 11101100110 | /ˈʌndə/        | unde   |
| 1896 | [undo](/bip39-word/undo/)         | 11101100111 | /ʌnˈduː/       | undo   |
| 1897 | [unfair](/bip39-word/unfair/)     | 11101101000 | /ʌnˈfeə/       | unfa   |
| 1898 | [unfold](/bip39-word/unfold/)     | 11101101001 | /ʌnˈfəʊld/     | unfo   |
| 1899 | [unhappy](/bip39-word/unhappy/)   | 11101101010 | /ʌnˈhæpi/      | unha   |
| 1900 | [uniform](/bip39-word/uniform/)   | 11101101011 | /ˈjuːnɪfɔːm/   | unif   |
| 1901 | [unique](/bip39-word/unique/)     | 11101101100 | /juːˈniːk/     | uniq   |
| 1902 | [unit](/bip39-word/unit/)         | 11101101101 | /ˈjuːnɪt/      | unit   |
| 1903 | [universe](/bip39-word/universe/) | 11101101110 | /ˈjuːnɪvɜːs/   | univ   |
| 1904 | [unknown](/bip39-word/unknown/)   | 11101101111 | /ʌnˈnəʊn/      | unkn   |
| 1905 | [unlock](/bip39-word/unlock/)     | 11101110000 | /ʌnˈlɒk/       | unlo   |
| 1906 | [until](/bip39-word/until/)       | 11101110001 | /ənˈtɪl/       | unti   |
| 1907 | [unusual](/bip39-word/unusual/)   | 11101110010 | /ʌnˈjuːʒʊəl/   | unus   |
| 1908 | [unveil](/bip39-word/unveil/)     | 11101110011 | /ʌnˈveɪl/      | unve   |
| 1909 | [update](/bip39-word/update/)     | 11101110100 | /ʌpˈdeɪt/      | upda   |
| 1910 | [upgrade](/bip39-word/upgrade/)   | 11101110101 | /ʌpˈɡreɪd/     | upgr   |
| 1911 | [uphold](/bip39-word/uphold/)     | 11101110110 | /ʌpˈhəʊld/     | upho   |
| 1912 | [upon](/bip39-word/upon/)         | 11101110111 | /əˈpɒn/        | upon   |
| 1913 | [upper](/bip39-word/upper/)       | 11101111000 | /ˈʌpə/         | uppe   |
| 1914 | [upset](/bip39-word/upset/)       | 11101111001 | /ʌpˈsɛt/       | upse   |
| 1915 | [urban](/bip39-word/urban/)       | 11101111010 | /ˈɜːbən/       | urba   |
| 1916 | [urge](/bip39-word/urge/)         | 11101111011 | /ɜːʤ/          | urge   |
| 1917 | [usage](/bip39-word/usage/)       | 11101111100 | /ˈjuːzɪʤ/      | usag   |
| 1918 | [use](/bip39-word/use/)           | 11101111101 | /juːz/         | use    |
| 1919 | [used](/bip39-word/used/)         | 11101111110 | /juːzd/        | used   |
| 1920 | [useful](/bip39-word/useful/)     | 11101111111 | /ˈjuːsfʊl/     | usef   |
| 1921 | [useless](/bip39-word/useless/)   | 11110000000 | /ˈjuːsləs/     | usel   |
| 1922 | [usual](/bip39-word/usual/)       | 11110000001 | /ˈjuːʒʊəl/     | usua   |
| 1923 | [utility](/bip39-word/utility/)   | 11110000010 | /ju(ː)ˈtɪlɪti/ | util   |

## Similar-looking words to check

 These 3 pairs differ by one letter, with at least one word starting with U. Both words are valid, so a slip between them passes the word check and only the checksum can catch it. 

- [enable](/bip39-word/enable/) [unable](/bip39-word/unable/)
- [surge](/bip39-word/surge/) [urge](/bip39-word/urge/)
- [use](/bip39-word/use/) [used](/bip39-word/used/)

[ Full BIP39 Wordlist (all 2048 words) ](/#wordlist)