diff --git a/include/ddc/kernels/splines/bsplines_non_uniform.hpp b/include/ddc/kernels/splines/bsplines_non_uniform.hpp
index 0c3cd4e84..18ed8dbb3 100644
--- a/include/ddc/kernels/splines/bsplines_non_uniform.hpp
+++ b/include/ddc/kernels/splines/bsplines_non_uniform.hpp
@@ -462,8 +462,8 @@ KOKKOS_INLINE_FUNCTION ddc::DiscreteElement<DDim> NonUniformBSplines<Tag, D>::
     std::array<double, degree()> left;
     std::array<double, degree()> right;
 
-    assert(x >= rmin());
-    assert(x <= rmax());
+    assert(x - rmin() >= -length() * 1e-14);
+    assert(rmax() - x >= -length() * 1e-14);
     assert(values.size() == degree() + 1);
 
     // 1. Compute cell index 'icell'
@@ -500,8 +500,8 @@ KOKKOS_INLINE_FUNCTION ddc::DiscreteElement<DDim> NonUniformBSplines<Tag, D>::
     std::array<double, degree()> left;
     std::array<double, degree()> right;
 
-    assert(x >= rmin());
-    assert(x <= rmax());
+    assert(x - rmin() >= -length() * 1e-14);
+    assert(rmax() - x >= -length() * 1e-14);
     assert(derivs.size() == degree() + 1);
 
     // 1. Compute cell index 'icell'
@@ -573,8 +573,8 @@ KOKKOS_INLINE_FUNCTION ddc::DiscreteElement<DDim> NonUniformBSplines<Tag, D>::
             std::experimental::extents<std::size_t, degree() + 1, degree() + 1>> const
             ndu(ndu_ptr.data());
 
-    assert(x >= rmin());
-    assert(x <= rmax());
+    assert(x - rmin() >= -length() * 1e-14);
+    assert(rmax() - x >= -length() * 1e-14);
     // assert(n >= 0); as long as n is unsigned
     assert(n <= degree());
     assert(derivs.extent(0) == 1 + degree());
@@ -663,8 +663,8 @@ KOKKOS_INLINE_FUNCTION ddc::DiscreteElement<NonUniformBsplinesKnots<DDim>> NonUn
         Tag,
         D>::Impl<DDim, MemorySpace>::find_cell_start(ddc::Coordinate<Tag> const& x) const
 {
-    assert(x <= rmax());
-    assert(x >= rmin());
+    assert(x - rmin() >= -length() * 1e-14);
+    assert(rmax() - x >= -length() * 1e-14);
 
     if (x == rmin())
         return m_break_point_domain.front();
diff --git a/include/ddc/kernels/splines/bsplines_uniform.hpp b/include/ddc/kernels/splines/bsplines_uniform.hpp
index f15fc54f6..722416fac 100644
--- a/include/ddc/kernels/splines/bsplines_uniform.hpp
+++ b/include/ddc/kernels/splines/bsplines_uniform.hpp
@@ -474,8 +474,8 @@ KOKKOS_INLINE_FUNCTION ddc::DiscreteElement<DDim> UniformBSplines<Tag, D>::Impl<
     double offset;
     int jmin;
 
-    assert(x >= rmin());
-    assert(x <= rmax());
+    assert(x - rmin() >= -length() * 1e-14);
+    assert(rmax() - x >= -length() * 1e-14);
     // assert(n >= 0); as long as n is unsigned
     assert(n <= degree());
     assert(derivs.extent(0) == 1 + degree());
@@ -554,8 +554,8 @@ KOKKOS_INLINE_FUNCTION void UniformBSplines<Tag, D>::Impl<DDim, MemorySpace>::ge
         double& offset,
         ddc::Coordinate<Tag> const& x) const
 {
-    assert(x >= rmin());
-    assert(x <= rmax());
+    assert(x - rmin() >= -length() * 1e-14);
+    assert(rmax() - x >= -length() * 1e-14);
 
     double const inv_dx = inv_step();
     if (x == rmin()) {