diff --git a/src/service/globals/mod.rs b/src/service/globals/mod.rs
index 3f98babe..3a514d5c 100644
--- a/src/service/globals/mod.rs
+++ b/src/service/globals/mod.rs
@@ -7,7 +7,7 @@ use std::{
 	time::Instant,
 };
 
-use conduwuit::{error, Config, Result};
+use conduwuit::{error, utils::bytes::pretty, Config, Result};
 use data::Data;
 use regex::RegexSet;
 use ruma::{OwnedEventId, OwnedRoomAliasId, OwnedServerName, OwnedUserId, ServerName, UserId};
@@ -93,13 +93,18 @@ impl crate::Service for Service {
 		Ok(Arc::new(s))
 	}
 
-	fn memory_usage(&self, out: &mut dyn Write) -> Result<()> {
-		let bad_event_ratelimiter = self
-			.bad_event_ratelimiter
-			.read()
-			.expect("locked for reading")
-			.len();
-		writeln!(out, "bad_event_ratelimiter: {bad_event_ratelimiter}")?;
+	fn memory_usage(&self, out: &mut dyn Write) -> Result {
+		let (ber_count, ber_bytes) = self.bad_event_ratelimiter.read()?.iter().fold(
+			(0_usize, 0_usize),
+			|(mut count, mut bytes), (event_id, _)| {
+				bytes = bytes.saturating_add(event_id.capacity());
+				bytes = bytes.saturating_add(size_of::<RateLimitState>());
+				count = count.saturating_add(1);
+				(count, bytes)
+			},
+		);
+
+		writeln!(out, "bad_event_ratelimiter: {ber_count} ({})", pretty(ber_bytes))?;
 
 		Ok(())
 	}
diff --git a/src/service/resolver/cache.rs b/src/service/resolver/cache.rs
index 3e961f4c..e309a129 100644
--- a/src/service/resolver/cache.rs
+++ b/src/service/resolver/cache.rs
@@ -6,7 +6,10 @@ use std::{
 };
 
 use arrayvec::ArrayVec;
-use conduwuit::{trace, utils::rand};
+use conduwuit::{
+	trace,
+	utils::{math::Expected, rand},
+};
 use ruma::{OwnedServerName, ServerName};
 
 use super::fed::FedDest;
@@ -113,6 +116,15 @@ impl CachedDest {
 	pub(crate) fn default_expire() -> SystemTime {
 		rand::timepoint_secs(60 * 60 * 18..60 * 60 * 36)
 	}
+
+	#[inline]
+	#[must_use]
+	pub fn size(&self) -> usize {
+		self.dest
+			.size()
+			.expected_add(self.host.len())
+			.expected_add(size_of_val(&self.expire))
+	}
 }
 
 impl CachedOverride {
@@ -126,4 +138,8 @@ impl CachedOverride {
 	pub(crate) fn default_expire() -> SystemTime {
 		rand::timepoint_secs(60 * 60 * 6..60 * 60 * 12)
 	}
+
+	#[inline]
+	#[must_use]
+	pub fn size(&self) -> usize { size_of_val(self) }
 }
diff --git a/src/service/resolver/fed.rs b/src/service/resolver/fed.rs
index 3986db8e..76fc6894 100644
--- a/src/service/resolver/fed.rs
+++ b/src/service/resolver/fed.rs
@@ -5,6 +5,7 @@ use std::{
 };
 
 use arrayvec::ArrayString;
+use conduwuit::utils::math::Expected;
 
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub enum FedDest {
@@ -76,6 +77,15 @@ impl FedDest {
 	pub fn default_port() -> PortString {
 		PortString::from(DEFAULT_PORT).expect("default port string")
 	}
+
+	#[inline]
+	#[must_use]
+	pub fn size(&self) -> usize {
+		match self {
+			| Self::Literal(saddr) => size_of_val(saddr),
+			| Self::Named(host, port) => host.len().expected_add(port.capacity()),
+		}
+	}
 }
 
 impl fmt::Display for FedDest {
diff --git a/src/service/resolver/mod.rs b/src/service/resolver/mod.rs
index e18cf0bd..6a6289b6 100644
--- a/src/service/resolver/mod.rs
+++ b/src/service/resolver/mod.rs
@@ -6,7 +6,7 @@ mod tests;
 
 use std::{fmt::Write, sync::Arc};
 
-use conduwuit::{Result, Server};
+use conduwuit::{utils, utils::math::Expected, Result, Server};
 
 use self::{cache::Cache, dns::Resolver};
 use crate::{client, Dep};
@@ -36,22 +36,25 @@ impl crate::Service for Service {
 		}))
 	}
 
-	fn memory_usage(&self, out: &mut dyn Write) -> Result<()> {
-		let resolver_overrides_cache = self
-			.cache
-			.overrides
-			.read()
-			.expect("locked for reading")
-			.len();
-		writeln!(out, "resolver_overrides_cache: {resolver_overrides_cache}")?;
+	fn memory_usage(&self, out: &mut dyn Write) -> Result {
+		use utils::bytes::pretty;
 
-		let resolver_destinations_cache = self
-			.cache
-			.destinations
-			.read()
-			.expect("locked for reading")
-			.len();
-		writeln!(out, "resolver_destinations_cache: {resolver_destinations_cache}")?;
+		let (oc_count, oc_bytes) = self.cache.overrides.read()?.iter().fold(
+			(0_usize, 0_usize),
+			|(count, bytes), (key, val)| {
+				(count.expected_add(1), bytes.expected_add(key.len()).expected_add(val.size()))
+			},
+		);
+
+		let (dc_count, dc_bytes) = self.cache.destinations.read()?.iter().fold(
+			(0_usize, 0_usize),
+			|(count, bytes), (key, val)| {
+				(count.expected_add(1), bytes.expected_add(key.len()).expected_add(val.size()))
+			},
+		);
+
+		writeln!(out, "resolver_overrides_cache: {oc_count} ({})", pretty(oc_bytes))?;
+		writeln!(out, "resolver_destinations_cache: {dc_count} ({})", pretty(dc_bytes))?;
 
 		Ok(())
 	}
diff --git a/src/service/rooms/state_accessor/mod.rs b/src/service/rooms/state_accessor/mod.rs
index fd132798..d89c8835 100644
--- a/src/service/rooms/state_accessor/mod.rs
+++ b/src/service/rooms/state_accessor/mod.rs
@@ -10,7 +10,11 @@ use std::{
 use conduwuit::{
 	err, error,
 	pdu::PduBuilder,
-	utils::{math::usize_from_f64, ReadyExt},
+	utils,
+	utils::{
+		math::{usize_from_f64, Expected},
+		ReadyExt,
+	},
 	Err, Error, PduEvent, Result,
 };
 use futures::StreamExt;
@@ -84,12 +88,35 @@ impl crate::Service for Service {
 		}))
 	}
 
-	fn memory_usage(&self, out: &mut dyn Write) -> Result<()> {
-		let server_visibility_cache = self.server_visibility_cache.lock().expect("locked").len();
-		writeln!(out, "server_visibility_cache: {server_visibility_cache}")?;
+	fn memory_usage(&self, out: &mut dyn Write) -> Result {
+		use utils::bytes::pretty;
 
-		let user_visibility_cache = self.user_visibility_cache.lock().expect("locked").len();
-		writeln!(out, "user_visibility_cache: {user_visibility_cache}")?;
+		let (svc_count, svc_bytes) = self.server_visibility_cache.lock()?.iter().fold(
+			(0_usize, 0_usize),
+			|(count, bytes), (key, _)| {
+				(
+					count.expected_add(1),
+					bytes
+						.expected_add(key.0.capacity())
+						.expected_add(size_of_val(&key.1)),
+				)
+			},
+		);
+
+		let (uvc_count, uvc_bytes) = self.user_visibility_cache.lock()?.iter().fold(
+			(0_usize, 0_usize),
+			|(count, bytes), (key, _)| {
+				(
+					count.expected_add(1),
+					bytes
+						.expected_add(key.0.capacity())
+						.expected_add(size_of_val(&key.1)),
+				)
+			},
+		);
+
+		writeln!(out, "server_visibility_cache: {svc_count} ({})", pretty(svc_bytes))?;
+		writeln!(out, "user_visibility_cache: {uvc_count} ({})", pretty(uvc_bytes))?;
 
 		Ok(())
 	}