diff --git a/core/src/event.rs b/core/src/event.rs
index 800aea7..343d0e6 100644
--- a/core/src/event.rs
+++ b/core/src/event.rs
@@ -1,20 +1,17 @@
-use core::{
-    fmt,
-    ops::{ControlFlow, RangeInclusive},
-};
+use core::{fmt, ops::ControlFlow};
 
 use crate::{
     key::{Key, ToKey},
     props::{ByRef, Chain, ErasedProps, Props},
     template::{Render, Template},
-    time::Timestamp,
+    time::Extent,
     value::{ToValue, Value},
     well_known::{MESSAGE_KEY, TEMPLATE_KEY, TIMESTAMP_KEY, TIMESTAMP_START_KEY},
 };
 
 #[derive(Clone)]
 pub struct Event<'a, P> {
-    ts: Option<RangeInclusive<Timestamp>>,
+    ts: Option<Extent>,
     tpl: Template<'a>,
     props: P,
 }
@@ -34,17 +31,9 @@ impl<'a, P: Props> fmt::Debug for Event<'a, P> {
 }
 
 impl<'a, P: Props> Event<'a, P> {
-    pub fn point(ts: impl Into<Option<Timestamp>>, tpl: Template<'a>, props: P) -> Self {
-        Event::spanned(ts.into().map(|ts| ts..=ts), tpl, props)
-    }
-
-    pub fn spanned(
-        ts: impl Into<Option<RangeInclusive<Timestamp>>>,
-        tpl: Template<'a>,
-        props: P,
-    ) -> Self {
+    pub fn new(ts: Option<impl Into<Extent>>, tpl: Template<'a>, props: P) -> Self {
         Event {
-            ts: ts.into(),
+            ts: ts.map(Into::into),
             tpl,
             props,
         }
@@ -58,18 +47,8 @@ impl<'a, P: Props> Event<'a, P> {
         self.tpl.by_ref()
     }
 
-    pub fn timestamp(&self) -> Option<Timestamp> {
-        self.ts.as_ref().map(|ts| *ts.start())
-    }
-
-    pub fn timespan(&self) -> Option<RangeInclusive<Timestamp>> {
-        self.ts.as_ref().and_then(|ts| {
-            if *ts.start() != *ts.end() {
-                Some(ts.clone())
-            } else {
-                None
-            }
-        })
+    pub fn extent(&self) -> Option<&Extent> {
+        self.ts.as_ref()
     }
 
     pub fn chain<U: Props>(self, other: U) -> Event<'a, Chain<P, U>> {
@@ -111,7 +90,7 @@ impl<'a, P: Props> Event<'a, P> {
 }
 
 pub struct AllProps<'a, P> {
-    ts: Option<RangeInclusive<Timestamp>>,
+    ts: Option<Extent>,
     tpl: Template<'a>,
     msg: Render<'a, &'a P>,
     props: ByRef<'a, P>,
@@ -123,8 +102,8 @@ impl<'a, P: Props> Props for AllProps<'a, P> {
         mut for_each: F,
     ) {
         if let Some(ref ts) = self.ts {
-            if *ts.start() != *ts.end() {
-                for_each(TIMESTAMP_START_KEY.to_key(), ts.start().to_value());
+            if let Some(start) = ts.start() {
+                for_each(TIMESTAMP_START_KEY.to_key(), start.to_value());
             }
 
             for_each(TIMESTAMP_KEY.to_key(), ts.end().to_value());
diff --git a/core/src/lib.rs b/core/src/lib.rs
index 7b67da1..f570eb8 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -2,6 +2,7 @@
 
 #[cfg(feature = "alloc")]
 extern crate alloc;
+extern crate core;
 
 pub mod ambient;
 pub mod ctxt;
diff --git a/core/src/time.rs b/core/src/time.rs
index 5e14a58..bc40675 100644
--- a/core/src/time.rs
+++ b/core/src/time.rs
@@ -1,4 +1,4 @@
-use core::{cmp, fmt, str, str::FromStr, time::Duration};
+use core::{cmp, fmt, ops::RangeInclusive, str, str::FromStr, time::Duration};
 
 use crate::{
     empty::Empty,
@@ -57,6 +57,77 @@ impl<'v> Value<'v> {
     }
 }
 
+#[derive(Clone)]
+pub struct Extent(ExtentInner);
+
+#[derive(Clone)]
+enum ExtentInner {
+    Point(Timestamp),
+    Span(RangeInclusive<Timestamp>),
+}
+
+impl fmt::Debug for Extent {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.0 {
+            ExtentInner::Point(ts) => fmt::Debug::fmt(&ts, f),
+            ExtentInner::Span(ref ts) => fmt::Debug::fmt(ts, f),
+        }
+    }
+}
+
+impl fmt::Display for Extent {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.0 {
+            ExtentInner::Point(ts) => fmt::Display::fmt(&ts, f),
+            ExtentInner::Span(ref ts) => {
+                fmt::Display::fmt(ts.start(), f)?;
+                write!(f, "..=")?;
+                fmt::Display::fmt(ts.end(), f)
+            }
+        }
+    }
+}
+
+impl Extent {
+    pub fn point(ts: Timestamp) -> Extent {
+        Extent(ExtentInner::Point(ts))
+    }
+
+    pub fn span(ts: RangeInclusive<Timestamp>) -> Extent {
+        if ts.start() == ts.end() {
+            Extent::point(*ts.end())
+        } else {
+            Extent(ExtentInner::Span(ts))
+        }
+    }
+
+    pub fn start(&self) -> Option<&Timestamp> {
+        match self.0 {
+            ExtentInner::Point(_) => None,
+            ExtentInner::Span(ref ts) => Some(ts.start()),
+        }
+    }
+
+    pub fn end(&self) -> &Timestamp {
+        match self.0 {
+            ExtentInner::Point(ref ts) => ts,
+            ExtentInner::Span(ref ts) => ts.end(),
+        }
+    }
+}
+
+impl From<Timestamp> for Extent {
+    fn from(point: Timestamp) -> Extent {
+        Extent::point(point)
+    }
+}
+
+impl From<RangeInclusive<Timestamp>> for Extent {
+    fn from(span: RangeInclusive<Timestamp>) -> Extent {
+        Extent::span(span)
+    }
+}
+
 pub trait Clock {
     fn now(&self) -> Option<Timestamp>;
 }
diff --git a/macros/src/emit.rs b/macros/src/emit.rs
index 0507b6a..b76abdd 100644
--- a/macros/src/emit.rs
+++ b/macros/src/emit.rs
@@ -13,21 +13,26 @@ pub struct ExpandTokens {
 }
 
 struct Args {
+    ts: TokenStream,
     to: TokenStream,
     when: TokenStream,
 }
 
 impl Parse for Args {
     fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
+        let mut ts = Arg::token_stream("ts", |expr| {
+            Ok(quote!(Some(emit::time::Extent::from(#expr))))
+        });
         let mut to = Arg::token_stream("to", |expr| Ok(quote!(#expr)));
         let mut when = Arg::token_stream("when", |expr| Ok(quote!(#expr)));
 
         args::set_from_field_values(
             input.parse_terminated(FieldValue::parse, Token![,])?.iter(),
-            [&mut to, &mut when],
+            [&mut ts, &mut to, &mut when],
         )?;
 
         Ok(Args {
+            ts: ts.take().unwrap_or_else(|| quote!(None)),
             to: to.take().unwrap_or_else(|| quote!(emit::empty::Empty)),
             when: when.take().unwrap_or_else(|| quote!(emit::empty::Empty)),
         })
@@ -46,6 +51,7 @@ pub fn expand_tokens(opts: ExpandTokens) -> Result<TokenStream, syn::Error> {
     let props_match_binding_tokens = props.match_binding_tokens();
     let props_tokens = props.match_bound_tokens();
 
+    let ts_tokens = args.ts;
     let to_tokens = args.to;
     let when_tokens = args.when;
 
@@ -64,6 +70,7 @@ pub fn expand_tokens(opts: ExpandTokens) -> Result<TokenStream, syn::Error> {
                 emit::#receiver_tokens(
                     #to_tokens,
                     #when_tokens,
+                    #ts_tokens,
                     #level_tokens,
                     #template_tokens,
                     #props_tokens,
diff --git a/macros/src/lib.rs b/macros/src/lib.rs
index c20aff2..c070ba5 100644
--- a/macros/src/lib.rs
+++ b/macros/src/lib.rs
@@ -23,6 +23,7 @@ mod fmt;
 mod hook;
 mod key;
 mod props;
+mod span;
 mod template;
 mod util;
 mod with;
@@ -67,7 +68,7 @@ Format a template.
 #[proc_macro]
 pub fn format(item: proc_macro::TokenStream) -> proc_macro::TokenStream {
     emit::expand_tokens(emit::ExpandTokens {
-        receiver: quote!(format),
+        receiver: quote!(__private::__format),
         level: quote!(default()),
         input: TokenStream::from(item),
     })
diff --git a/macros/src/span.rs b/macros/src/span.rs
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/macros/src/span.rs
@@ -0,0 +1 @@
+
diff --git a/src/lib.rs b/src/lib.rs
index eb2f546..6bd597a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,8 +4,9 @@
 extern crate alloc;
 
 use core::future::Future;
+use std::ops::RangeInclusive;
 
-use emit_core::{ctxt::Ctxt, filter::Filter, target::Target, time::Clock};
+use emit_core::{ctxt::Ctxt, filter::Filter, target::Target};
 
 #[doc(inline)]
 pub use emit_macros::*;
@@ -21,7 +22,11 @@ pub mod ctxt {
     pub use emit_core::ctxt::*;
 }
 
-use emit_core::{value::ToValue, well_known::WellKnown};
+use emit_core::{
+    time::{Clock, Extent},
+    value::ToValue,
+    well_known::WellKnown,
+};
 
 pub use self::{
     event::Event, key::Key, level::Level, props::Props, template::Template, time::Timestamp,
@@ -42,13 +47,18 @@ mod setup;
 pub fn emit(evt: &Event<impl Props>) {
     let ambient = emit_core::ambient::get();
 
+    let tpl = evt.template();
+    let props = evt.props();
+
     base_emit(
         ambient,
         ambient,
         ambient,
-        ambient,
-        evt.template(),
-        evt.props(),
+        evt.extent()
+            .cloned()
+            .or_else(|| ambient.now().map(Extent::point)),
+        tpl,
+        props,
     );
 }
 
@@ -57,14 +67,12 @@ fn base_emit(
     to: impl Target,
     when: impl Filter,
     ctxt: impl Ctxt,
-    clock: impl Clock,
+    ts: Option<Extent>,
     tpl: Template,
     props: impl Props,
 ) {
     ctxt.with_current(|ctxt| {
-        let ts = clock.now();
-
-        let evt = Event::point(ts, tpl, props.chain(ctxt));
+        let evt = Event::new(ts, tpl, props.chain(ctxt));
 
         if when.matches(&evt) {
             to.event(&evt);
diff --git a/src/macro_hooks.rs b/src/macro_hooks.rs
index 8194af0..fba726a 100644
--- a/src/macro_hooks.rs
+++ b/src/macro_hooks.rs
@@ -1,22 +1,20 @@
-use core::{any::Any, fmt};
-
-use emit_core::value::{ToValue, Value};
+use core::{any::Any, fmt, future::Future};
 
 use emit_core::{
     ambient,
     ctxt::Ctxt,
     filter::Filter,
-    id::IdSource,
     level::Level,
     props::Props,
     target::Target,
     template::Template,
-    time::Clock,
-    well_known::{WellKnown, LEVEL_KEY},
+    time::{Clock, Extent},
+    value::Value,
+    well_known::LEVEL_KEY,
 };
+
 #[cfg(feature = "std")]
 use std::error::Error;
-use std::future::Future;
 
 use crate::{
     base_emit, base_with, base_with_future,
@@ -302,14 +300,21 @@ impl<'a> __PrivateKeyHook for Key<'a> {
 }
 
 #[track_caller]
-pub fn __emit(to: impl Target, when: impl Filter, lvl: Level, tpl: Template, props: impl Props) {
+pub fn __emit(
+    to: impl Target,
+    when: impl Filter,
+    ts: Option<Extent>,
+    lvl: Level,
+    tpl: Template,
+    props: impl Props,
+) {
     let ambient = ambient::get();
 
     base_emit(
         to.and(ambient),
         when.and(ambient),
         ambient,
-        ambient,
+        ts.or_else(|| ambient.now().map(Extent::point)),
         tpl,
         (LEVEL_KEY, lvl).chain(props),
     );
diff --git a/targets/otlp/src/logs.rs b/targets/otlp/src/logs.rs
index 1b9b172..c525670 100644
--- a/targets/otlp/src/logs.rs
+++ b/targets/otlp/src/logs.rs
@@ -63,7 +63,8 @@ impl OtlpLogsTargetBuilder {
 impl emit_core::target::Target for OtlpLogsTarget {
     fn event<P: emit_core::props::Props>(&self, evt: &emit_core::event::Event<P>) {
         let time_unix_nano = evt
-            .timestamp()
+            .extent()
+            .map(|ts| ts.end())
             .map(|ts| ts.to_unix().as_nanos() as u64)
             .unwrap_or_default();
 
diff --git a/targets/term/src/lib.rs b/targets/term/src/lib.rs
index 0b19e0b..aa8d625 100644
--- a/targets/term/src/lib.rs
+++ b/targets/term/src/lib.rs
@@ -53,7 +53,7 @@ impl emit::target::Target for Stdout {
 fn print(out: &BufferWriter, buf: &mut Buffer, evt: &emit::Event<impl emit::Props>) {
     let mut header_empty = true;
 
-    if let Some(ts) = evt.timestamp() {
+    if let Some(ts) = evt.extent() {
         let _ = write!(buf, "[{:.0}", ts);
 
         header_empty = false;