diff --git a/base/asyncevent.jl b/base/asyncevent.jl
index a26945bbb1105..498fb054ecd02 100644
--- a/base/asyncevent.jl
+++ b/base/asyncevent.jl
@@ -272,8 +272,8 @@ julia> begin
 3
 ```
 """
-function Timer(cb::Function, timeout::Real; interval::Real=0.0)
-    timer = Timer(timeout, interval=interval)
+function Timer(cb::Function, timeout; kwargs...)
+    timer = Timer(timeout; kwargs...)
     t = @task begin
         unpreserve_handle(timer)
         while _trywait(timer)
diff --git a/stdlib/Dates/src/periods.jl b/stdlib/Dates/src/periods.jl
index 9b7e29496e642..744b084fe2260 100644
--- a/stdlib/Dates/src/periods.jl
+++ b/stdlib/Dates/src/periods.jl
@@ -465,3 +465,7 @@ days(c::Year)        = 365.2425 * value(c)
 days(c::Quarter)     = 91.310625 * value(c)
 days(c::Month)       = 30.436875 * value(c)
 days(c::CompoundPeriod) = isempty(c.periods) ? 0.0 : Float64(sum(days, c.periods))
+seconds(x::Nanosecond) = value(x) / 1000000000
+seconds(x::Microsecond) = value(x) / 1000000
+seconds(x::Millisecond) = value(x) / 1000
+seconds(x::Period) = value(Second(x))
diff --git a/stdlib/Dates/src/types.jl b/stdlib/Dates/src/types.jl
index 1d9769a05bd3d..a96d183bbc590 100644
--- a/stdlib/Dates/src/types.jl
+++ b/stdlib/Dates/src/types.jl
@@ -460,14 +460,14 @@ Base.hash(x::Time, h::UInt) =
     hash(hour(x), hash(minute(x), hash(second(x),
         hash(millisecond(x), hash(microsecond(x), hash(nanosecond(x), h))))))
 
-Base.sleep(duration::Period) = sleep(toms(duration) / 1000)
+Base.sleep(duration::Period) = sleep(seconds(duration))
 
 function Base.Timer(delay::Period; interval::Period=Second(0))
-    Timer(toms(delay) / 1000, interval=toms(interval) / 1000)
+    Timer(seconds(delay), interval=seconds(interval))
 end
 
 function Base.timedwait(testcb, timeout::Period; pollint::Period=Millisecond(100))
-    timedwait(testcb, toms(timeout) / 1000, pollint=toms(pollint) / 1000)
+    timedwait(testcb, seconds(timeout), pollint=seconds(pollint))
 end
 
 Base.OrderStyle(::Type{<:AbstractTime}) = Base.Ordered()
diff --git a/stdlib/Dates/test/periods.jl b/stdlib/Dates/test/periods.jl
index 7b23ffcb5d4e1..9ed4a21f96ad6 100644
--- a/stdlib/Dates/test/periods.jl
+++ b/stdlib/Dates/test/periods.jl
@@ -343,6 +343,15 @@ end
     @test Dates.days(Dates.Hour(24)) == 1
     @test Dates.days(d) == 1
     @test Dates.days(w) == 7
+
+    @test Dates.seconds(ns) == 0.000000001
+    @test Dates.seconds(us) == 0.000001
+    @test Dates.seconds(ms) == 0.001
+    @test Dates.seconds(s) == 1
+    @test Dates.seconds(mi) == 60
+    @test Dates.seconds(h) == 3600
+    @test Dates.seconds(d) == 86400
+    @test Dates.seconds(w) == 604800
 end
 @testset "issue #9214" begin
     @test 2s + (7ms + 1ms) == (2s + 7ms) + 1ms == 1ms + (2s + 7ms) == 1ms + (1s + 7ms) + 1s == 1ms + (2s + 3d + 7ms) + (-3d) == (1ms + (2s + 3d)) + (7ms - 3d) == (1ms + (2s + 3d)) - (3d - 7ms)
diff --git a/stdlib/Dates/test/types.jl b/stdlib/Dates/test/types.jl
index 8823e56e41a2f..3bd11f80540d7 100644
--- a/stdlib/Dates/test/types.jl
+++ b/stdlib/Dates/test/types.jl
@@ -273,6 +273,11 @@ end
 
 end
 
+@testset "timer" begin
+    @test hasmethod(Timer, (Period,))
+    @test hasmethod(Timer, (Function, Period))
+end
+
 @testset "timedwait" begin
     @test timedwait(() -> false, Second(0); pollint=Millisecond(1)) === :timed_out
 end