diff --git a/matlab/numgrad.m b/matlab/numgrad.m
index 69809efa3..13c4510ab 100644
--- a/matlab/numgrad.m
+++ b/matlab/numgrad.m
@@ -24,7 +24,7 @@ function [g, badg] = numgrad(fcn,f0,x,epsilon,varargin)
 
 fh = NaN;
 
-delta = 1e-6;
+delta = epsilon;
 n=length(x);
 tvec=delta*eye(n);
 g=zeros(n,1);
diff --git a/matlab/numgrad3.m b/matlab/numgrad3.m
index b62d0ac85..3891e11c5 100644
--- a/matlab/numgrad3.m
+++ b/matlab/numgrad3.m
@@ -31,7 +31,7 @@
 f1 = NaN;
 f2 = NaN;
 
-delta = 1e-6;
+delta = epsilon;
 n=length(x);
 tvec=delta*eye(n);
 g=zeros(n,1);
diff --git a/matlab/numgrad5.m b/matlab/numgrad5.m
index c1bfb07ec..5062f898e 100644
--- a/matlab/numgrad5.m
+++ b/matlab/numgrad5.m
@@ -35,7 +35,7 @@ f2 = NaN;
 f3 = NaN;
 f4 = NaN;
 
-delta = 1e-6;
+delta = epsilon;
 n=length(x);
 tvec=delta*eye(n);
 g=zeros(n,1);