diff --git a/pkgs/racket-test-core/tests/racket/will.rktl b/pkgs/racket-test-core/tests/racket/will.rktl
index 1250b290ac..a0723614e9 100644
--- a/pkgs/racket-test-core/tests/racket/will.rktl
+++ b/pkgs/racket-test-core/tests/racket/will.rktl
@@ -254,7 +254,7 @@
   (define t (parameterize ([current-custodian c])
               (thread (lambda ()
                         (semaphore-wait s)
-                        (define b (make-phantom-bytes (expt 2 29)))
+                        (define b (make-phantom-bytes (expt 2 bits)))
                         (test #t phantom-bytes? b)
                         (test #f phantom-bytes? 0)
                         (semaphore-wait s)
@@ -266,16 +266,16 @@
   (define mc (current-memory-use c))
   (semaphore-post s)
   (sync (system-idle-evt))
-  (test #t > (current-memory-use) (+ m (expt 2 28)))
+  (test #t > (current-memory-use) (+ m (expt 2 (sub1 bits))))
   (collect-garbage)
-  (test #t > (current-memory-use) (+ m (expt 2 28)))
-  (test #t > (current-memory-use c) (+ mc (expt 2 28)))
+  (test #t > (current-memory-use) (+ m (expt 2 (sub1 bits))))
+  (test #t > (current-memory-use c) (+ mc (expt 2 (sub1 bits))))
   (semaphore-post s)
   (sync (system-idle-evt))
-  (test #t < (current-memory-use) (+ m (expt 2 28)))
+  (test #t < (current-memory-use) (+ m (expt 2 (sub1 bits))))
   (collect-garbage)
-  (test #t < (current-memory-use) (+ m (expt 2 28)))
-  (test #t < (current-memory-use c) (+ mc (expt 2 28)))
+  (test #t < (current-memory-use) (+ m (expt 2 (sub1 bits))))
+  (test #t < (current-memory-use c) (+ mc (expt 2 (sub1 bits))))
   (semaphore-post s)
 
   (let ([done? #f])