Blob.estimateBlobCount

Estimate number of blobs needed for data

Try it Live

Run Blob examples in the interactive playground

Calculation

Each blob stores up to 131,064 bytes of data:

import { Blob } from 'tevm';

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

// Formula: ceil(dataLength / maxPerBlob)
function estimate(dataLength: number): number {
  return Math.ceil(dataLength / maxPerBlob);
}

// Examples
console.log(estimate(1));         // 1 blob
console.log(estimate(131_064));   // 1 blob (exactly fits)
console.log(estimate(131_065));   // 2 blobs (1 byte over)
console.log(estimate(262_128));   // 2 blobs
console.log(estimate(300_000));   // 3 blobs
console.log(estimate(786_384));   // 6 blobs (max)

Size Limits

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 transaction: ${maxData} bytes`);    // 786,384
console.log(`Max blobs per transaction: ${Blob.MAX_PER_TRANSACTION}`); // 6

// At limit
console.log(Blob.estimateBlobCount(maxData));     // 6

// Over limit (would fail in splitData)
console.log(Blob.estimateBlobCount(maxData + 1)); // 7

Use Cases

Pre-Flight Validation

import { Blob } from 'tevm';

function canFitInTransaction(data: Uint8Array): boolean {
  const blobCount = Blob.estimateBlobCount(data);
  return blobCount <= Blob.MAX_PER_TRANSACTION;
}

if (!canFitInTransaction(largeData)) {
  console.error('Data too large for single transaction');
  // Split into multiple transactions or compress
}

Cost Estimation

import { Blob } from 'tevm';

async function estimateBlobCost(
  data: Uint8Array,
  provider: any
): Promise<bigint> {
  const blobCount = Blob.estimateBlobCount(data);
  const blobBaseFee = await provider.getBlobBaseFee();

  return Blob.calculateGas(blobCount, blobBaseFee);
}

const cost = await estimateBlobCost(data, provider);
console.log(`Estimated cost: ${cost / 10n**9n} gwei`);

Batch Planning

import { Blob } from 'tevm';

function planBatches(items: Uint8Array[]): Uint8Array[][] {
  const batches: Uint8Array[][] = [];
  let currentBatch: Uint8Array[] = [];
  let currentBlobCount = 0;

  for (const item of items) {
    const itemBlobCount = Blob.estimateBlobCount(item);

    if (currentBlobCount + itemBlobCount > Blob.MAX_PER_TRANSACTION) {
      // Start new batch
      batches.push(currentBatch);
      currentBatch = [item];
      currentBlobCount = itemBlobCount;
    } else {
      // Add to current batch
      currentBatch.push(item);
      currentBlobCount += itemBlobCount;
    }
  }

  if (currentBatch.length > 0) {
    batches.push(currentBatch);
  }

  return batches;
}

Edge Cases

import { Blob } from 'tevm';

// Empty data
console.log(Blob.estimateBlobCount(0)); // 1 blob (minimum)

// Exactly 1 blob
const exactlyOne = new Uint8Array(131_064);
console.log(Blob.estimateBlobCount(exactlyOne)); // 1

// 1 byte over
const oneOver = new Uint8Array(131_065);
console.log(Blob.estimateBlobCount(oneOver)); // 2

// Maximum
const maxData = new Uint8Array(786_384);
console.log(Blob.estimateBlobCount(maxData)); // 6

See Also

• splitData - Split data into blobs
• calculateGas - Calculate gas cost
• fromData - Create single blob