How to create and launch a cryptocurrency token with TokenMint?

I am using web3 to transfer tokens by using web3.eth.sendSignedTransaction.

When I am setting the parameter rawTx like

var rawTx = {

     "from"      : walletbase,             "nonce"     : value,       "gasPrice"  : web3.utils.toHex(2000000000), //2 gwei       "gasLimit"  : estimateGas,       "to"        : contractAddr,            "value"     : "0x00",       "data"      : data,       // "chainId"    : 3   } 

I want to set the gasLimit dynamically. I tried to calculate the gasLimit by using web3.eth.estimateGas like:

web3.eth.estimateGas({

          to  : toAddress,           data: data           }) 

But the value is lower than need. I always got error like:

Error: Transaction ran out of gas. Please provide more gas:

Do you have better way to calculate the gasLimit? Thank you.