diff --git a/src/DataInterpolations.jl b/src/DataInterpolations.jl
index 7e998519..18249393 100644
--- a/src/DataInterpolations.jl
+++ b/src/DataInterpolations.jl
@@ -29,7 +29,7 @@ include("show.jl")
 
 (interp::AbstractInterpolation)(t::Number) = _interpolate(interp, t)
 (interp::AbstractInterpolation)(t::Number, i::Integer) = _interpolate(interp, t, i)
-(interp::AbstractInterpolation)(t::AbstractVector) = interp(similar(t, eltype(interp)), t)
+(interp::AbstractInterpolation)(t::AbstractVector) = interp(similar(t, promote_type(eltype(interp), eltype(t))), t)
 function (interp::AbstractInterpolation)(u::AbstractVector, t::AbstractVector)
     iguess = firstindex(interp.t)
     @inbounds for i in eachindex(u, t)
diff --git a/test/derivative_tests.jl b/test/derivative_tests.jl
index 241a4fc2..a3f08ddf 100644
--- a/test/derivative_tests.jl
+++ b/test/derivative_tests.jl
@@ -219,3 +219,15 @@ end
     ts = 0.0:0.1:1.0
     @test all(map(ti -> symfunc(ti) == derivative(f, ti), ts))
 end
+
+@testset "Jacobian tests" begin
+    u = rand(5)
+    t = 0:4
+    interp = LinearInterpolation(u, t,extrapolate=true)
+    grad1 = ForwardDiff.derivative(interp,2.4)
+
+    myvec = rand(20).*4.0
+    interp(myvec)
+
+    grad = ForwardDiff.jacobian(interp,myvec)
+end