Roll Your Own Seed Phrase

Step 1 · prepare

Set up a private workspace.

Gather these six things before we get started.

Dice

One or more six-sided dice.

Rolling setup

A lidded box (e.g. shoebox, tupperware) OR a cup and a hard rolling tray.

Two printouts

BitsToWords and the manually searchable BIP-39 word list.

A pen

Use it to write each converted bit into the printed sheet.

An offline device

A hardware wallet or (permanently!) offline laptop that can .

A private room

No cameras, phones, observers or electronic snitches like Alexa.

Dice quality

Use plain, well-made dice. Avoid decorative, novelty, damaged, or visibly uneven dice.

My rolling setup

Step 2 · decide

Choose an encoding, then your phrase length.

First choose how to convert dice results into bits. Then choose a phrase length and prepare the matching worksheet.

Dice-to-bit method

Oren's variable-length mapping uses every face: 1–4 produce two bits; 5–6 produce one.

Expect about 77 physical rolls on average.

Binary quantization uses every result: faces 1–3 mean 0, and faces 4–6 mean 1.

You will make exactly 128 rolls.

Phrase length

Before rolling: select the matching Bit-to-word worksheet and fill its Identifier field with a name (non-secret) so you can recognize this seed backup later.

1

⚀00

⚁01

⚂10

⚃11

⚄0

⚅1

Faces 1–4 add two bits; faces 5–6 add one.

2

Identifier: My first dummy seed phrase

I selected my encoding and phrase length.I entered a name in the Identifier field.

Step 3 · roll and record

Roll, convert, and repeat.

1 Put all dice in the lidded box. Shake hard at least ten times; each shake should make the dice travel and collide audibly inside. Then gently tip the settled dice to one edge.
2 Open the box without moving dice by hand. Read left to right; if needed, read the next row front to back.
3 Convert each result using the selected method, shown on the right.
4 Enter the resulting bit(s) in the next boxes; discard any that would cross the checksum boundary.

Unclear result? If a die is cocked or ambiguous, discard the whole batch and roll the complete batch again.

Repeat: steps 1-4, until you reach the checksum boundary in the last word.

1

⚄⚂⚀

Shake hard at least ten times.

2

⚄⚂⚀

Tip to align, then read left → right.

3

Convert the face value

⚀⚁⚂⚃⚄⚅

↓↓↓↓↓↓

0001101101

4

5

I rolled 128 bits with this same rolling method, reading order, and conversion rule throughout.

Step 4 · bits to words

Look up one 11-bit group (word) at a time.

Use the printed references. For each of the numbered boxes (except the last one):

1Use P (first 3 bits) to choose the page.
2Use C (next 3 bits) to choose the column.
3Use R (last 5 bits): first 2 choose the block; last 3 choose the row in it.
4Write the word you found into the empty space beneath its bits.

1

11010010100

2

1

11010010100

3

1

11010010100

Page P6 with column C4, block 10, and row R20 highlighted

4

1

11010010100

spoon

I found all 11 words.

Step 5 · finish

Let the checksum finish the last word.

For your selected 12-word phrase, keep the bits you rolled and leave the final 4 checksum bits for the wallet.

1 Identify the 16 allowed last-word choices matching your rolled bits.
- The first 3 bits determine the page.
- The next 3 bits determine the column.
- Bit 7 selects the upper half (0) or lower half (1) of that column.
The first 3 bits determine the page.
2 Enter the first 11 words as an existing seed phrase.
3 Depending on your wallet select a final word (consult its documentation if needed).
4 Verify the wallet's proposed final word against that range.

Remember: checksum bits are determined by the earlier bits. They do not reduce the randomness you created with dice.

1

→

BIP39 word-list page with the upper half of one column highlighted

Half a column: 16 candidate words

I identified the valid range of final words.I verified the final word proposed by the wallet keeps my rolled bits and is in the valid range.

Step 6 · complete

Make your own seed phrase
one roll at a time.

Set up a private workspace.

Dice

Rolling setup

Two printouts

A pen

An offline device

A private room

Dice quality

My rolling setup

Choose an encoding, then your phrase length.

Dice-to-bit method

Phrase length

Roll, convert, and repeat.

Look up one 11-bit group (word) at a time.

Let the checksum finish the last word.

Congratulations—
you made your own seed phrase.

Make your own seed phraseone roll at a time.

Set up a private workspace.

Dice

Rolling setup

Two printouts

A pen

An offline device

A private room

Dice quality

My rolling setup

Choose an encoding, then your phrase length.

Dice-to-bit method

Phrase length

Roll, convert, and repeat.

Look up one 11-bit group (word) at a time.

Let the checksum finish the last word.

Congratulations—you made your own seed phrase.

Make your own seed phrase
one roll at a time.

Congratulations—
you made your own seed phrase.