diff --git a/src/interval.jl b/src/interval.jl
index bace476f..a95fd5fb 100644
--- a/src/interval.jl
+++ b/src/interval.jl
@@ -189,6 +189,14 @@ function Base.convert(::Type{T}, interval::Interval{T}) where T
     end
 end
 
+function Base.convert(::Type{<:Interval{T}}, interval::Interval{S,L,R}) where {T,S,L,R}
+    return Interval{T,L,R}(first(interval), last(interval))
+end
+
+Base.promote_rule(::Type{Interval{T,L1,R1}}, ::Type{Interval{S,L2,R2}}) where {T,S,L1,R1,L2,R2} = Interval{promote_type(T,S), <:Union{L1,L2}, <:Union{R1,R2}}
+# hacky way to fix situations where T and S are the same but L and R are different
+Base.not_sametype(x::Tuple{Interval{T,L1,R1}, Interval{T,L2,R2}}, y::Tuple{Interval{T,L1,R1}, Interval{T,L2,R2}}) where {T,L1,R1,L2,R2} = nothing
+
 ##### DISPLAY #####
 
 function Base.show(io::IO, interval::Interval{T,L,R}) where {T,L,R}
diff --git a/test/interval.jl b/test/interval.jl
index bca310d5..472cc9f3 100644
--- a/test/interval.jl
+++ b/test/interval.jl
@@ -85,6 +85,7 @@ isinf(::TimeType) = false
         @test_throws DomainError convert(Int, Interval{Closed, Open}(10, 10))
         @test convert(Int, Interval{Closed, Closed}(10, 10)) == 10
         @test_throws DomainError convert(Int, Interval{Closed, Closed}(10, 11))
+        @test convert(Interval{Float64, Closed, Closed}, Interval(1,2)) == Interval{Float64, Closed, Closed}(1.0,2.0)
 
         for T in (Date, DateTime)
             dt = T(2013, 2, 13)
@@ -101,6 +102,20 @@ isinf(::TimeType) = false
         @test eltype(Interval{Float64}(1,2)) == Float64
     end
 
+    @testset "promotion" begin
+        for (a1, b1, _) in test_values
+            for (a2, b2, _) in test_values
+                for (L1, R1) in BOUND_PERMUTATIONS
+                    for (L2, R2) in BOUND_PERMUTATIONS
+                        interval1 = Interval{L1, R1}(a1, b1)
+                        interval2 = Interval{L2, R2}(a2, b2)
+                        @test promote(interval1, interval2) == (Interval{L1,R1}(promote(a1, b1)...), Interval{L2,R2}(promote(a2, b2)...))
+                    end
+                end
+            end
+        end
+    end
+
     @testset "accessors" begin
         for (a, b, _) in test_values
             for (L, R) in BOUND_PERMUTATIONS