diff --git a/src/circuit/gadget/ecc/chip/mul.rs b/src/circuit/gadget/ecc/chip/mul.rs
index eebb1a02..edb66fca 100644
--- a/src/circuit/gadget/ecc/chip/mul.rs
+++ b/src/circuit/gadget/ecc/chip/mul.rs
@@ -43,8 +43,8 @@ const INCOMPLETE_HI_LEN: usize = INCOMPLETE_LEN / 2;
 
 // Bits k_{254} to k_{4} inclusive are used in incomplete addition.
 // The `lo` half is k_{129} to k_{4} inclusive (length 126 bits).
-const INCOMPLETE_LO_RANGE: Range<usize> = (INCOMPLETE_LEN / 2)..INCOMPLETE_LEN;
-const INCOMPLETE_LO_LEN: usize = (INCOMPLETE_LEN / 2) + 1;
+const INCOMPLETE_LO_RANGE: Range<usize> = INCOMPLETE_HI_LEN..INCOMPLETE_LEN;
+const INCOMPLETE_LO_LEN: usize = INCOMPLETE_LEN - INCOMPLETE_HI_LEN;
 
 // Bits k_{3} to k_{1} inclusive are used in complete addition.
 // Bit k_{0} is handled separately.