What is the unit of measurement used in GasPrice and GasLimit?

Question

I did a check, in ethgasstation the current safeLow = 15GWei, which is equal = 15,000,000,000 wei

However, when I issue eth.getBlock("latest") what I get was:

> eth.getBlock("latest")
{
  difficulty: 3462313604051830,
  extraData: "0x73656f3130",
  gasLimit: 8000029,
  gasUsed: 7991485,

The gasLimit and gasUsed here are way lower than the safeLow value. So I can only guess that they are using different units in measurement.

Otherwise I really do not know what might had gone wrong. Because I had never enter so many zeros when I wanted to send an ETH transaction.

Answer 1

"gas" is an abstract unit of work. Operations inside the EVM require a certain amount of gas.

What is the unit of measurement used in GasPrice and GasLimit?

gasPrice is the cost per unit of work that you pay to the miner who mines your transaction. The units are therefore wei / gas. Gas prices form a market: the higher price you use, the more chance a miner will decide to include your transaction in a block.

The 15 GWei is the amount you're currently willing to spend for each unit of work done by the EVM. (The current safeLow, standard and fast values on ethgasstation.info reflect the current state of the gas price market.)

If we're talking about a given block, the gasLimit is the total amount of "EVM work" that the transactions inside the block can equate to. The limit is currently around 8 million gas.

gasUsed is the amount of gas that was used for a particular. The closer this value is to the gasLimit, the fuller the block can be considered.

See What is meant by the term "gas"? for more details.