diff --git a/mempool/estimatefee.go b/mempool/estimatefee.go
index 3546f6b3..55fe4810 100644
--- a/mempool/estimatefee.go
+++ b/mempool/estimatefee.go
@@ -563,7 +563,7 @@ func (ef *FeeEstimator) EstimateFee(numBlocks uint32) (BtcPerKilobyte, error) {
 	if numBlocks > estimateFeeDepth {
 		return -1, fmt.Errorf(
 			"can only estimate fees for up to %d blocks from now",
-			estimateFeeBinSize)
+			estimateFeeDepth)
 	}
 
 	// If there are no cached results, generate them.