Hidden fee (about 15% of sum) while send #27120

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Hello,

My wallet is 3KxxEaECid1H1h5Ya2XnjsxLx8fK6TToQj - 18 transactions total.

I sent 0.1BTC, but in blockchain I found 2 transactions: my own (0.1BTC) + unknown fee (0.01999241BTC) - 20% of sum! TXID: 70a951a496a809597b79753be7b4f05a7b13ece1d09d8d0ae643b0190ace1fba

Next I sent 0.1BTC, but in blockchain I found 2 transactions: my own (0.1BTC) + unknown fee (0.00997949BTC) - 10% of sum! TXID: 60488ac88ed0390cb24b4659aa2256c5eacf4dee102749cd828ea18c293ea090

I do not understand how this could happen. In Bitcoin Core I see ONLY my transactions, but blockchain show me more 2 transactions to unknown wallets (bc1qg3ds029ydsum9pgldpfhmcp94sncrvhqzltp5q, 3Be8ZPdgUqxXbagjJ5imvG7nYZzgLxaHHR)

So, total balance in blockchain is less then in Bitcoin Core on this amount (0.02997189BTC) Bitcoin Core show me 1.38994437 BTC, but blockchain show me 1.35997247BTC (minus two fees above)

What is my really balance? What are these hidden payments? Tell me more about it, please. What can I do to solve this problems in future? Screens from my Bitcoin Core is attached below. Thanks!

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System information

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Bitcoin Core version v0.18.0 (64-bit) - from official site.

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Linux blockchain 4.15.0-48-generic #51-Ubuntu SMP Wed Apr 3 08:28:49 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

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Are those "hidden payments" your own change?

Yes, Bitcoin Core will use a new address to send the change to. If you add up the amounts on the other addresses, you will reach the Bitcoin Core balance:

1.35997247 + 0.0199924 + 0.00997949 = 1.38994436

Thanks for your help. I read about UTXO-model, so wallets with sum 0.0199924 and 0.00997949 is my addresses too, but for changes? I will be very grateful if you explain to me: how did these changes formed? From what amount? On my specific example, if possible. I do not understand the algorithm of this process for now.

Questions about how Bitcoin works are off-topic here, but you can find resource in other places. For example see https://bitcoin.stackexchange.com/a/738/208 about how change works.

Thanks to all! The main meaning is here:

Because the client manages coins in a particular way, it doesn't make sense to try to view coins it is managing with any kind of explorer. It's specifically trying to obscure the fact that all the coins are related. Those kinds of services are intended to monitor recieved funds, not managed funds.

Where did you send it to what wallet ?