diff --git a/library/bignum_mod_raw.c b/library/bignum_mod_raw.c
index 8f7270a..bf72c18 100644
--- a/library/bignum_mod_raw.c
+++ b/library/bignum_mod_raw.c
@@ -131,18 +131,11 @@
                              mbedtls_mpi_uint *T)
 {
     /* Standard (A * B) multiplication stored into pre-allocated T
-     *  buffer of fixed limb size of (2N + 1).
+     * buffer of fixed limb size of (2N + 1).
      *
-     *  The space may not not fully filled by when
-     *  MBEDTLS_MPI_MOD_REP_OPT_RED is used, where we only need
-     *  (2N) or (2N-1) limbs (depending on limb size and curve).
-     *
-     *  The 521-bit Weierstrass curve is the only
-     *  that which requires a limb size of (2N). */
-    const size_t T_limbs = (N->bits == 521) ?
-                           BITS_TO_LIMBS(N->bits * 2) + 1 :
-                           BITS_TO_LIMBS(N->bits * 2);
-
+     * The space may not not fully filled by when
+     * MBEDTLS_MPI_MOD_REP_OPT_RED is used. */
+    const size_t T_limbs = BITS_TO_LIMBS(N->bits) * 2;
     switch (N->int_rep) {
         case MBEDTLS_MPI_MOD_REP_MONTGOMERY:
             mbedtls_mpi_core_montmul(X, A, B, N->limbs, N->p, N->limbs,
diff --git a/library/ecp_curves.c b/library/ecp_curves.c
index e3bcc87..a4fa663 100644
--- a/library/ecp_curves.c
+++ b/library/ecp_curves.c
@@ -4922,7 +4922,7 @@
 static int ecp_mod_p192(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width = 2 * ((192 + biL - 1) / biL);
+    size_t expected_width = BITS_TO_LIMBS(192) * 2;
     MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
     ret = mbedtls_ecp_mod_p192_raw(N->p, expected_width);
 
@@ -4936,7 +4936,7 @@
     mbedtls_mpi_uint c = 0, last_carry[WIDTH] = { 0 };
     mbedtls_mpi_uint *p, *end;
 
-    if (Nn != 2*((192 + biL - 1)/biL)) {
+    if (Nn != BITS_TO_LIMBS(192) * 2) {
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }
 
@@ -5082,7 +5082,7 @@
 static int ecp_mod_p224(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width =  2 * 224 / biL;
+    size_t expected_width = BITS_TO_LIMBS(224) * 2;
     MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
     ret = mbedtls_ecp_mod_p224_raw(N->p, expected_width);
 cleanup:
@@ -5092,7 +5092,7 @@
 MBEDTLS_STATIC_TESTABLE
 int mbedtls_ecp_mod_p224_raw(mbedtls_mpi_uint *X, size_t X_limbs)
 {
-    if (X_limbs != 2 * 224 / biL) {
+    if (X_limbs != BITS_TO_LIMBS(224) * 2) {
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }
 
@@ -5135,7 +5135,7 @@
 static int ecp_mod_p256(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width = 2 * 256 / biL;
+    size_t expected_width = BITS_TO_LIMBS(256) * 2;
     MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
     ret = mbedtls_ecp_mod_p256_raw(N->p, expected_width);
 cleanup:
@@ -5145,7 +5145,7 @@
 MBEDTLS_STATIC_TESTABLE
 int mbedtls_ecp_mod_p256_raw(mbedtls_mpi_uint *X, size_t X_limbs)
 {
-    if (X_limbs != 2 * 256 / biL) {
+    if (X_limbs != BITS_TO_LIMBS(256) * 2) {
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }
 
@@ -5215,7 +5215,7 @@
 static int ecp_mod_p384(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width = 2 * ((384 + biL - 1) / biL);
+    size_t expected_width = BITS_TO_LIMBS(384) * 2;
     MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
     ret = mbedtls_ecp_mod_p384_raw(N->p, expected_width);
 cleanup:
@@ -5225,7 +5225,7 @@
 MBEDTLS_STATIC_TESTABLE
 int mbedtls_ecp_mod_p384_raw(mbedtls_mpi_uint *X, size_t X_limbs)
 {
-    if (X_limbs != 2*((384 + biL - 1)/biL)) {
+    if (X_limbs != BITS_TO_LIMBS(384) * 2) {
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }
 
@@ -5337,7 +5337,7 @@
 static int ecp_mod_p521(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width = 2 * P521_WIDTH;
+    size_t expected_width = BITS_TO_LIMBS(521) * 2;
     MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
     ret = mbedtls_ecp_mod_p521_raw(N->p, expected_width);
 cleanup:
@@ -5349,7 +5349,7 @@
 {
     mbedtls_mpi_uint carry = 0;
 
-    if (X_limbs != 2 * P521_WIDTH || X[2 * P521_WIDTH - 1] != 0) {
+    if (X_limbs != BITS_TO_LIMBS(521) * 2) {
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }
 
@@ -5423,7 +5423,7 @@
 static int ecp_mod_p255(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width = 2 * P255_WIDTH;
+    size_t expected_width = BITS_TO_LIMBS(255) * 2;
     MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
     ret = mbedtls_ecp_mod_p255_raw(N->p, expected_width);
 cleanup:
@@ -5434,7 +5434,7 @@
 int mbedtls_ecp_mod_p255_raw(mbedtls_mpi_uint *X, size_t X_Limbs)
 {
 
-    if (X_Limbs != 2 * P255_WIDTH) {
+    if (X_Limbs != BITS_TO_LIMBS(255) * 2) {
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }
 
@@ -5492,7 +5492,7 @@
 static int ecp_mod_p448(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width = 2 * ((448 + biL - 1) / biL);
+    size_t expected_width = BITS_TO_LIMBS(448) * 2;
 
     /* This is required as some tests and use cases do not pass in a Bignum of
      * the correct size, and expect the growth to be done automatically, which
@@ -5522,7 +5522,7 @@
     size_t round;
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
 
-    if (X_limbs <= P448_WIDTH) {
+    if (X_limbs != BITS_TO_LIMBS(448) * 2) {
         return 0;
     }
 
@@ -5734,7 +5734,7 @@
 static int ecp_mod_p192k1(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width = 2 * ((192 + biL - 1) / biL);
+    size_t expected_width = BITS_TO_LIMBS(192) * 2;
     MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
     ret = mbedtls_ecp_mod_p192k1_raw(N->p, expected_width);
 
@@ -5750,7 +5750,7 @@
                                   0x01, 0x00, 0x00, 0x00)
     };
 
-    if (X_limbs != 2 * ((192 + biL - 1) / biL)) {
+    if (X_limbs != BITS_TO_LIMBS(192) * 2) {
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }
 
@@ -5768,7 +5768,7 @@
 static int ecp_mod_p224k1(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width =  2 * 224 / biL;
+    size_t expected_width = BITS_TO_LIMBS(224) * 2;
     MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
     ret = mbedtls_ecp_mod_p224k1_raw(N->p, expected_width);
 
@@ -5784,7 +5784,7 @@
                                   0x01, 0x00, 0x00, 0x00)
     };
 
-    if (X_limbs != 2 * 224 / biL) {
+    if (X_limbs !=  BITS_TO_LIMBS(224) * 2) {
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }
 
@@ -5802,7 +5802,7 @@
 static int ecp_mod_p256k1(mbedtls_mpi *N)
 {
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
-    size_t expected_width = 2 * ((256 + biL - 1) / biL);
+    size_t expected_width = BITS_TO_LIMBS(256) * 2;
     MBEDTLS_MPI_CHK(mbedtls_mpi_grow(N, expected_width));
     ret = mbedtls_ecp_mod_p256k1_raw(N->p, expected_width);
 
@@ -5818,7 +5818,7 @@
                                   0x01, 0x00, 0x00, 0x00)
     };
 
-    if (X_limbs != 2 * ((256 + biL - 1) / biL)) {
+    if (X_limbs != BITS_TO_LIMBS(256) * 2) {
         return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     }