diff --git a/eval.c b/eval.c
index fcad8f1..19cdd48 100644
--- a/eval.c
+++ b/eval.c
@@ -40,7 +40,7 @@ int main(void)
 		return EXIT_FAILURE;
 	}
 
-	unsigned correct = 0;
+	unsigned solved = 0, errors = 0;
 	char res[NCELLS], sol[NCELLS];
 	for (unsigned i = 0; i < NPUZZ; ++i) {
 		if (fread(&res, sizeof(char), NCELLS, rfp) != NCELLS) {
@@ -52,12 +52,20 @@ int main(void)
 			return EXIT_FAILURE;
 		}
 
-		if (memcmp(res, sol, NCELLS) == 0)
-			++correct;
+		bool allcells = true;
+		for (unsigned j = 0; j < NCELLS; ++j) {
+			if (res[j] != sol[j]) {
+				allcells = false;
+				if (res[j] != '0')
+					++errors;
+			}
+		}
+		if (allcells)
+			++solved;
 	}
 
-	double pc = 1e2 * (double)correct / (double)NPUZZ;
-	printf("%u/%u correct (%.2f%%)\n", correct, NPUZZ, pc);
+	double pc = 1e2 * (double)solved / (double)NPUZZ;
+	printf("%u/%u (%.2f%%) solved, %u errors\n", solved, NPUZZ, pc, errors);
 
 	fclose(rfp);
 	fclose(sfp);