> ## Documentation Index
> Fetch the complete documentation index at: https://voltaire.tevm.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# Blob.splitData

> Split large data into multiple blobs

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  Run Blob examples in the interactive playground
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<Tabs />

## Data Distribution

Each blob stores a chunk with encoding:

```
Blob 1: [length_1][chunk_1][padding]
Blob 2: [length_2][chunk_2][padding]
Blob 3: [length_3][chunk_3][padding]
...

Max per blob: 131,064 bytes (SIZE - 8 for length prefix)
```

### Example: Size Calculation

```typescript theme={null}
import { Blob } from 'tevm';

const maxPerBlob = Blob.SIZE - 8; // 131,064 bytes
console.log(`Max data per blob: ${maxPerBlob}`);

const data = new Uint8Array(300_000);
const blobCount = Math.ceil(data.length / maxPerBlob);
console.log(`Requires ${blobCount} blobs`); // 3

// Verify with estimateBlobCount
console.log(Blob.estimateBlobCount(data)); // 3
```

## Maximum Data Size

```typescript theme={null}
import { Blob } from 'tevm';

const maxPerBlob = Blob.SIZE - 8;
const maxData = maxPerBlob * Blob.MAX_PER_TRANSACTION;

console.log(`Max per blob: ${maxPerBlob} bytes`); // 131,064
console.log(`Max per tx: ${maxData} bytes`); // 786,384
console.log(`Max blobs per tx: ${Blob.MAX_PER_TRANSACTION}`); // 6

// This succeeds (exactly at limit)
const atLimit = new Uint8Array(maxData);
const blobs = Blob.splitData(atLimit);
console.log(blobs.length); // 6

// This fails (exceeds limit)
try {
  const tooLarge = new Uint8Array(maxData + 1);
  Blob.splitData(tooLarge);
} catch (e) {
  console.error(e); // "Data too large: requires 7 blobs (max 6)"
}
```

## Reconstruction

Use `joinData()` to reconstruct original data:

```typescript theme={null}
import { Blob } from 'tevm';

const original = new Uint8Array(300_000);
// ... fill with data ...

// Split
const blobs = Blob.splitData(original);

// Reconstruct
const reconstructed = Blob.joinData(blobs);

// Verify
console.log(reconstructed.length === original.length); // true
console.log(Blob.equals(reconstructed, original)); // true
```

## Gas Estimation

```typescript theme={null}
import { Blob } from 'tevm';

const data = new Uint8Array(300_000);
const blobCount = Blob.estimateBlobCount(data);

// Calculate gas cost
const blobBaseFee = 50_000_000n; // 50 gwei
const blobGas = Blob.calculateGas(blobCount, blobBaseFee);

console.log(`${blobCount} blobs required`);
console.log(`Blob gas cost: ${blobGas / 10n**9n} gwei`);
```

## See Also

* [joinData](./joinData) - Reconstruct data from blobs
* [estimateBlobCount](./estimateBlobCount) - Estimate blob count
* [fromData](./fromData) - Encode single blob
* [toData](./toData) - Extract blob data