For example if btc's rate is $45,000/btc right now, and you bought 1 btc, and later the rate becomes $46,000, it would show you $1,000.
And if it's $44,000, it would show you $-1,000...and so on.
Something like this...

Did you try BitUniverse? I am using BitUniverse since the beginning of their journey and found it very helpful to track your portfolio. Its supports auto-tracking your balance and profit from exchanges or wallets, You just need to import your API key from the exchange. They support 100+ exchanges, It's a real-time bitcoin and altcoin ticker.