How large are the Ethereum block headers?

Question

I am interested in knowing the block header size to estimate the overhead of running an Ethereum light client.

Answer 1

Ok, so according to the Yellow paper (section 4.4), we have several fields in the block header:

1. parentHash, 256 bits
2. ommersHash, 256 bits
3. beneficiary, 160 bits
4. stateRoot, 256 bits
5. transactionsRoot, 256 bits
6. receiptsRoot, 256 bits
7. logsBloom, 256 bytes (see here)
8. difficulty, big int scalar
9. number, big int scalar
10. gasLimit, big int scalar
11. gasUsed, big int scalar
12. timestamp, big int scalar
13. extraData, (up to) 256 bits
14. mixHash, 256 bits
15. nonce, 64 bits

Summing everything up we get:

1. 256*7+160+64 + 8*256 = 4064 bits (508 bytes)
2. 5 variable length scalars