diff --git a/src/implementations/eig.jl b/src/implementations/eig.jl
index 9b785898..01e4eccd 100644
--- a/src/implementations/eig.jl
+++ b/src/implementations/eig.jl
@@ -9,8 +9,7 @@ copy_input(::Union{typeof(eig_trunc), typeof(eig_trunc_no_error)}, A) = copy_inp
 copy_input(::typeof(eig_full), A::Diagonal) = copy(A)
 
 function check_input(::typeof(eig_full!), A::AbstractMatrix, DV, ::AbstractAlgorithm)
-    m, n = size(A)
-    m == n || throw(DimensionMismatch("square input matrix expected"))
+    m = LinearAlgebra.checksquare(A)
     D, V = DV
     @assert D isa Diagonal && V isa AbstractMatrix
     @check_size(D, (m, m))
@@ -20,17 +19,16 @@ function check_input(::typeof(eig_full!), A::AbstractMatrix, DV, ::AbstractAlgor
     return nothing
 end
 function check_input(::typeof(eig_vals!), A::AbstractMatrix, D, ::AbstractAlgorithm)
-    m, n = size(A)
-    m == n || throw(DimensionMismatch("square input matrix expected"))
+    m = LinearAlgebra.checksquare(A)
     @assert D isa AbstractVector
-    @check_size(D, (n,))
+    @check_size(D, (m,))
     @check_scalar(D, A, complex)
     return nothing
 end
 
 function check_input(::typeof(eig_full!), A::AbstractMatrix, DV, ::DiagonalAlgorithm)
-    m, n = size(A)
-    ((m == n) && isdiag(A)) || throw(DimensionMismatch("diagonal input matrix expected"))
+    m = LinearAlgebra.checksquare(A)
+    isdiag(A) || throw(DimensionMismatch("diagonal input matrix expected"))
     D, V = DV
     @assert D isa Diagonal && V isa AbstractMatrix
     @check_size(D, (m, m))
@@ -40,10 +38,10 @@ function check_input(::typeof(eig_full!), A::AbstractMatrix, DV, ::DiagonalAlgor
     return nothing
 end
 function check_input(::typeof(eig_vals!), A::AbstractMatrix, D, ::DiagonalAlgorithm)
-    m, n = size(A)
-    ((m == n) && isdiag(A)) || throw(DimensionMismatch("diagonal input matrix expected"))
+    m = LinearAlgebra.checksquare(A)
+    isdiag(A) || throw(DimensionMismatch("diagonal input matrix expected"))
     @assert D isa AbstractVector
-    @check_size(D, (n,))
+    @check_size(D, (m,))
     @check_scalar(D, A, complex)
     return nothing
 end
diff --git a/src/implementations/eigh.jl b/src/implementations/eigh.jl
index 19a190b1..d17e25e8 100644
--- a/src/implementations/eigh.jl
+++ b/src/implementations/eigh.jl
@@ -11,8 +11,7 @@ copy_input(::typeof(eigh_full), A::Diagonal) = copy(A)
 check_hermitian(A, ::AbstractAlgorithm) = check_hermitian(A)
 check_hermitian(A, alg::Algorithm) = check_hermitian(A; atol = get(alg.kwargs, :hermitian_tol, default_hermitian_tol(A)))
 function check_hermitian(A; atol::Real = default_hermitian_tol(A), rtol::Real = 0)
-    m, n = size(A)
-    m == n || throw(DimensionMismatch("square input matrix expected"))
+    LinearAlgebra.checksquare(A)
     ishermitian(A; atol, rtol) ||
         throw(DomainError(A, "Hermitian matrix was expected. Use `project_hermitian` to project onto the nearest hermitian matrix."))
     return nothing
diff --git a/src/implementations/gen_eig.jl b/src/implementations/gen_eig.jl
index f4a6a7f5..043da2d9 100644
--- a/src/implementations/gen_eig.jl
+++ b/src/implementations/gen_eig.jl
@@ -6,12 +6,9 @@ end
 copy_input(::typeof(gen_eig_vals), A, B) = copy_input(gen_eig_full, A, B)
 
 function check_input(::typeof(gen_eig_full!), A::AbstractMatrix, B::AbstractMatrix, WV, ::AbstractAlgorithm)
-    ma, na = size(A)
-    mb, nb = size(B)
-    ma == na || throw(DimensionMismatch("square input matrix A expected"))
-    mb == nb || throw(DimensionMismatch("square input matrix B expected"))
-    ma == mb || throw(DimensionMismatch("first dimension of input matrices expected to match"))
-    na == nb || throw(DimensionMismatch("second dimension of input matrices expected to match"))
+    ma = LinearAlgebra.checksquare(A)
+    mb = LinearAlgebra.checksquare(B)
+    ma == mb || throw(DimensionMismatch(lazy"Expected matching input sizes, dimensions are $ma and $mb"))
     W, V = WV
     @assert W isa Diagonal && V isa AbstractMatrix
     @check_size(W, (ma, ma))
@@ -23,13 +20,11 @@ function check_input(::typeof(gen_eig_full!), A::AbstractMatrix, B::AbstractMatr
     return nothing
 end
 function check_input(::typeof(gen_eig_vals!), A::AbstractMatrix, B::AbstractMatrix, W, ::AbstractAlgorithm)
-    ma, na = size(A)
-    mb, nb = size(B)
-    ma == na || throw(DimensionMismatch("square input matrix A expected"))
-    mb == nb || throw(DimensionMismatch("square input matrix B expected"))
-    ma == mb || throw(DimensionMismatch("dimension of input matrices expected to match"))
+    ma = LinearAlgebra.checksquare(A)
+    mb = LinearAlgebra.checksquare(B)
+    ma == mb || throw(DimensionMismatch(lazy"Expected matching input sizes, dimensions are $ma and $mb"))
     @assert W isa AbstractVector
-    @check_size(W, (na,))
+    @check_size(W, (ma,))
     @check_scalar(W, A, complex)
     @check_scalar(W, B, complex)
     return nothing
diff --git a/src/implementations/schur.jl b/src/implementations/schur.jl
index 3cad9e0f..a193c912 100644
--- a/src/implementations/schur.jl
+++ b/src/implementations/schur.jl
@@ -5,23 +5,21 @@ copy_input(::typeof(schur_vals), A) = copy_input(eig_vals, A)
 
 # check input
 function check_input(::typeof(schur_full!), A::AbstractMatrix, TZv, ::AbstractAlgorithm)
-    m, n = size(A)
-    m == n || throw(DimensionMismatch("square input matrix expected"))
+    m = LinearAlgebra.checksquare(A)
     T, Z, vals = TZv
     @assert T isa AbstractMatrix && Z isa AbstractMatrix && vals isa AbstractVector
     @check_size(T, (m, m))
     @check_scalar(T, A)
     @check_size(Z, (m, m))
     @check_scalar(Z, A)
-    @check_size(vals, (n,))
+    @check_size(vals, (m,))
     @check_scalar(vals, A, complex)
     return nothing
 end
 function check_input(::typeof(schur_vals!), A::AbstractMatrix, vals, ::AbstractAlgorithm)
-    m, n = size(A)
-    m == n || throw(DimensionMismatch("square input matrix expected"))
+    m = LinearAlgebra.checksquare(A)
     @assert vals isa AbstractVector
-    @check_size(vals, (n,))
+    @check_size(vals, (m,))
     @check_scalar(vals, A, complex)
     return nothing
 end