diff --git a/base/range.jl b/base/range.jl
index 6979e3575ffa2..caac244b703b2 100644
--- a/base/range.jl
+++ b/base/range.jl
@@ -207,10 +207,10 @@ let smallint = (Int === Int64 ?
 
     function length{T <: smallint}(r::StepRange{T})
         isempty(r) && return int(0)
-        div(int(r.stop+r.step - r.start), int(r.step))
+        div(int(r.stop)+int(r.step) - int(r.start), int(r.step))
     end
 
-    length{T <: smallint}(r::UnitRange{T}) = int(r.stop - r.start + 1)
+    length{T <: smallint}(r::UnitRange{T}) = int(r.stop) - int(r.start) + 1
 end
 
 first{T}(r::OrdinalRange{T}) = oftype(T, r.start)
diff --git a/test/ranges.jl b/test/ranges.jl
index f0d5bc281b23d..b72f30c458497 100644
--- a/test/ranges.jl
+++ b/test/ranges.jl
@@ -363,3 +363,12 @@ for f in (mean, median)
         @test_approx_eq f(2:0.1:n) f([2:0.1:n])
     end
 end
+
+# issue #8531
+let smallint = (Int === Int64 ?
+                (Int8,Uint8,Int16,Uint16,Int32,Uint32) :
+                (Int8,Uint8,Int16,Uint16))
+    for T in smallint
+        @test length(typemin(T):typemax(T)) == 2^(8*sizeof(T))
+    end
+end