Given a Bitcoin transaction as JSON data, how can I determine the number of confirmations?

Question

According to blockchain.info, 4,198 confirmations have been received on the following Bitcoin transaction at the time of this writing. Give then following Bitcoin transaction as JSON (ref: transaction on blockhain.info as JSON) how can I determine the number of confirmations?

Transaction as JSON

{
   "ver":1,
   "inputs":[
      {
         "sequence":4294967295,
         "witness":"",
         "prev_out":{
            "spent":true,
            "spending_outpoints":[
               {
                  "tx_index":0,
                  "n":0
               }
            ],
            "tx_index":0,
            "type":0,
            "addr":"1BiYTVfoAWpEf5vTCVyWgWzsbdTbi3X4Lb",
            "value":4371338,
            "n":1,
            "script":"76a914758c92328cb8f0d5a9e2bc6a1b27b6fdf83fa86588ac"
         },
         "script":"483045022100f6d8e0e386079721dc286d25c88c5cddd8733ee3d93247f3ff0127e8aa7dcb9a02206ce2b7e524e4796e93688442dcc95bb7c8e2bcf3a46ac660633fac3e0becfd5e012102a9dba5ef4653f48190bf6b12130f001fe14cda8b8e2e06bf2e96b9cf3c442503"
      }
   ],
   "weight":760,
   "block_height":615893,
   "relayed_by":"0.0.0.0",
   "out":[
      {
         "spent":true,
         "spending_outpoints":[
            {
               "tx_index":0,
               "n":0
            }
         ],
         "tx_index":0,
         "type":0,
         "addr":"3BMEXDcDGPjGGR6MHiFiHRPfz6LeGeYYM3",
         "value":4366812,
         "n":0,
         "script":"a91469f3746a2b4246695de6ae4fd0d2c27221b1cd9d87"
      }
   ],
   "lock_time":0,
   "size":190,
   "block_index":0,
   "time":1580790109,
   "tx_index":0,
   "vin_sz":1,
   "hash":"406fe52a8cb99cfdc3ed6cc3e2ef461608e369943a9c1f4132421d3de425e66c",
   "vout_sz":1
}

Answer 1

Confirmations are nothing but just the number of blocks added after the block the transaction was added in. So accordingly, during the time of writing, the current block is 620093 and your transaction was added in block 615893

So if you subtract these two , current block - tx added block(620093 - 615893 = 4200), you will get the total number of confiramtions, which is near to your block confirmations (4198)

Hope this was helpful. Have a great day!