diff --git a/core/src/test/java/bisq/core/btc/TxFeeEstimationServiceTest.java b/core/src/test/java/bisq/core/btc/TxFeeEstimationServiceTest.java
new file mode 100644
index 0000000000..70fd45b512
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+++ b/core/src/test/java/bisq/core/btc/TxFeeEstimationServiceTest.java
@@ -0,0 +1,123 @@
+/*
+ * This file is part of Bisq.
+ *
+ * Bisq is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Bisq is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Bisq. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package bisq.core.btc;
+
+import bisq.core.btc.wallet.BtcWalletService;
+
+import org.bitcoinj.core.Coin;
+import org.bitcoinj.core.InsufficientMoneyException;
+
+import java.util.List;
+
+import org.powermock.core.classloader.annotations.PowerMockIgnore;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+@RunWith(PowerMockRunner.class)
+@PrepareForTest(BtcWalletService.class)
+@PowerMockIgnore({"com.sun.org.apache.xerces.*", "javax.xml.*", "org.xml.*"})
+public class TxFeeEstimationServiceTest {
+
+    @Test
+    public void testGetEstimatedTxSize() throws InsufficientMoneyException {
+        List<Coin> outputValues = List.of(Coin.valueOf(2000), Coin.valueOf(3000));
+        int initialEstimatedTxSize;
+        Coin txFeePerByte;
+        BtcWalletService btcWalletService = mock(BtcWalletService.class);
+        int result;
+        int realTxSize;
+        Coin txFee;
+
+        initialEstimatedTxSize = 260;
+        txFeePerByte = Coin.valueOf(10);
+        realTxSize = 260;
+
+        txFee = txFeePerByte.multiply(initialEstimatedTxSize);
+        when(btcWalletService.getEstimatedFeeTxSize(outputValues, txFee)).thenReturn(realTxSize);
+        result = TxFeeEstimationService.getEstimatedTxSize(outputValues, initialEstimatedTxSize, txFeePerByte, btcWalletService);
+        assertEquals(260, result);
+
+
+        // TODO check how to use the mocking framework for repeated calls
+        // The btcWalletService.getEstimatedFeeTxSize returns 0 at repeated calls in the while loop....
+       /* initialEstimatedTxSize = 260;
+        txFeePerByte = Coin.valueOf(10);
+        realTxSize = 2600;
+
+        txFee = txFeePerByte.multiply(initialEstimatedTxSize);
+        when(btcWalletService.getEstimatedFeeTxSize(outputValues, txFee)).thenReturn(realTxSize);
+        result = TxFeeEstimationService.getEstimatedTxSize(outputValues, initialEstimatedTxSize, txFeePerByte, btcWalletService);
+        assertEquals(2600, result);
+
+        initialEstimatedTxSize = 2600;
+        txFeePerByte = Coin.valueOf(10);
+        realTxSize = 260;
+
+        txFee = txFeePerByte.multiply(initialEstimatedTxSize);
+        when(btcWalletService.getEstimatedFeeTxSize(outputValues, txFee)).thenReturn(realTxSize);
+        result = TxFeeEstimationService.getEstimatedTxSize(outputValues, initialEstimatedTxSize, txFeePerByte, btcWalletService);
+        assertEquals(260, result);*/
+    }
+
+    @Test
+    public void testIsInTolerance() {
+        int estimatedSize;
+        int txSize;
+        double tolerance;
+        boolean result;
+
+        estimatedSize = 100;
+        txSize = 100;
+        tolerance = 0.0001;
+        result = TxFeeEstimationService.isInTolerance(estimatedSize, txSize, tolerance);
+        assertTrue(result);
+
+        estimatedSize = 100;
+        txSize = 200;
+        tolerance = 0.2;
+        result = TxFeeEstimationService.isInTolerance(estimatedSize, txSize, tolerance);
+        assertFalse(result);
+
+        estimatedSize = 120;
+        txSize = 100;
+        tolerance = 0.2;
+        result = TxFeeEstimationService.isInTolerance(estimatedSize, txSize, tolerance);
+        assertTrue(result);
+
+        estimatedSize = 200;
+        txSize = 100;
+        tolerance = 1;
+        result = TxFeeEstimationService.isInTolerance(estimatedSize, txSize, tolerance);
+        assertTrue(result);
+
+        estimatedSize = 201;
+        txSize = 100;
+        tolerance = 1;
+        result = TxFeeEstimationService.isInTolerance(estimatedSize, txSize, tolerance);
+        assertFalse(result);
+    }
+}