diff --git a/Makefile b/Makefile
index f4dad5f6..350c100c 100644
--- a/Makefile
+++ b/Makefile
@@ -693,24 +693,24 @@ bench-widths: $(BENCH_CSV)
 			write,stat,read \
 		-bprobe='%(case)s+%(probe)s' \
 		-Fi='min(enumerate())' \
-		-freaded="avg(ffrac( \
+		-freaded="avg(saturate(ffrac( \
 			float(bench_readed)/float(bench_reads), \
 			max(1, $$( \
 				./scripts/bench.py -R$(BENCH_RUNNER) $(BENCHFLAGS) \
 						--list-implicit-defines \
-					| sed -n 's/^READ_WIDTH=\(.*\)/\1/p'))))" \
-		-fprogged="avg(ffrac( \
+					| sed -n 's/^READ_WIDTH=\(.*\)/\1/p')))))" \
+		-fprogged="avg(saturate(ffrac( \
 			float(bench_progged)/float(bench_progs), \
 			max(1, $$( \
 				./scripts/bench.py -R$(BENCH_RUNNER) $(BENCHFLAGS) \
 						--list-implicit-defines \
-					| sed -n 's/^PROG_WIDTH=\(.*\)/\1/p'))))" \
-		-ferased="avg(ffrac( \
+					| sed -n 's/^PROG_WIDTH=\(.*\)/\1/p')))))" \
+		-ferased="avg(saturate(ffrac( \
 			float(bench_erased)/float(bench_erases), \
 			max(1, $$( \
 				./scripts/bench.py -R$(BENCH_RUNNER) $(BENCHFLAGS) \
 						--list-implicit-defines \
-					| sed -n 's/^ERASE_WIDTH=\(.*\)/\1/p'))))" \
+					| sed -n 's/^ERASE_WIDTH=\(.*\)/\1/p')))))" \
 		$(SUMMARYFLAGS))
 
 ## Show heap/stack/disk usage
diff --git a/scripts/csv.py b/scripts/csv.py
index 3c0dbdda..392c77a6 100755
--- a/scripts/csv.py
+++ b/scripts/csv.py
@@ -1099,6 +1099,18 @@ class CsvExpr:
             else:
                 return v.b
 
+    @func('saturate', 'a')
+    class Saturate(Expr):
+        """Limit to total part of a fraction"""
+        def eval(self, fields={}, state=None):
+            v = self.a.eval(fields, state)
+            if not hasattr(v, '__frac__'):
+                return v
+            elif isinstance(v, CsvFrac):
+                return CsvFrac(min(max(v.a, CsvInt(0)), v.b), v.b)
+            elif isinstance(v, CsvFfrac):
+                return CsvFfrac(min(max(v.a, CsvFloat(0)), v.b), v.b)
+
     @func('abs', 'a')
     class Abs(Expr):
         """Absolute value"""