diff --git a/CHANGELOG.md b/CHANGELOG.md
index c7d61176..e0ac5aa4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [0.6.3]/[0.7.0] - Unreleased
+## [0.6.4]/[0.7.0] - Unreleased
+
+## [0.6.3] - Unreleased
+
+## Bug Fixes
+
+- [#542](https://github.com/ClementTsang/bottom/pull/542): Fixes missing config options in the default generated config file.
+- [#545](https://github.com/ClementTsang/bottom/pull/545): Fixes inaccurate memory usage/totals in macOS and Linux.
 
 ## [0.6.2] - 2021-06-26
 
diff --git a/src/app/data_harvester/memory/heim.rs b/src/app/data_harvester/memory/heim.rs
index 5319b1b3..6e455510 100644
--- a/src/app/data_harvester/memory/heim.rs
+++ b/src/app/data_harvester/memory/heim.rs
@@ -33,14 +33,46 @@ pub async fn get_mem_data(
 pub async fn get_ram_data() -> crate::utils::error::Result<Option<MemHarvest>> {
     let memory = heim::memory::memory().await?;
 
-    let mem_total_in_kb = memory.total().get::<heim::units::information::kibibyte>();
+    let (mem_total_in_kib, mem_used_in_kib) = {
+        #[cfg(target_os = "linux")]
+        {
+            // For Linux, the "kilobyte" value in the .total call is actually kibibytes - see
+            // https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/deployment_guide/s2-proc-meminfo
+            //
+            // Heim parses this as kilobytes (https://github.com/heim-rs/heim/blob/master/heim-memory/src/sys/linux/memory.rs#L82)
+            // even though it probably shouldn't...
+
+            use heim::memory::os::linux::MemoryExt;
+            (
+                memory.total().get::<heim::units::information::kilobyte>(),
+                memory.used().get::<heim::units::information::kibibyte>(),
+            )
+        }
+        #[cfg(target_os = "macos")]
+        {
+            use heim::memory::os::macos::MemoryExt;
+            (
+                memory.total().get::<heim::units::information::kibibyte>(),
+                memory.active().get::<heim::units::information::kibibyte>()
+                    + memory.wire().get::<heim::units::information::kibibyte>(),
+            )
+        }
+        #[cfg(target_os = "windows")]
+        {
+            let mem_total_in_kib = memory.total().get::<heim::units::information::kibibyte>();
+            (
+                mem_total_in_kib,
+                mem_total_in_kib
+                    - memory
+                        .available()
+                        .get::<heim::units::information::kibibyte>(),
+            )
+        }
+    };
 
     Ok(Some(MemHarvest {
-        mem_total_in_kib: mem_total_in_kb,
-        mem_used_in_kib: mem_total_in_kb
-            - memory
-                .available()
-                .get::<heim::units::information::kibibyte>(),
+        mem_total_in_kib,
+        mem_used_in_kib,
     }))
 }
 
diff --git a/src/data_conversion.rs b/src/data_conversion.rs
index 1efc6db4..6548e0b6 100644
--- a/src/data_conversion.rs
+++ b/src/data_conversion.rs
@@ -300,22 +300,19 @@ pub fn convert_mem_labels(
     current_data: &data_farmer::DataCollection,
 ) -> (Option<(String, String)>, Option<(String, String)>) {
     /// Returns the unit type and denominator for given total amount of memory in kibibytes.
-    ///
-    /// Yes, this function is a bit of a lie.  But people seem to generally expect, say, GiB when what they actually
-    /// wanted calculated was GiB.
     fn return_unit_and_denominator_for_mem_kib(mem_total_kib: u64) -> (&'static str, f64) {
         if mem_total_kib < 1024 {
             // Stay with KiB
-            ("KB", 1.0)
-        } else if mem_total_kib < 1_048_576 {
+            ("KiB", 1.0)
+        } else if mem_total_kib < MEBI_LIMIT {
             // Use MiB
-            ("MB", 1024.0)
-        } else if mem_total_kib < 1_073_741_824 {
+            ("MiB", KIBI_LIMIT_F64)
+        } else if mem_total_kib < GIBI_LIMIT {
             // Use GiB
-            ("GB", 1_048_576.0)
+            ("GiB", MEBI_LIMIT_F64)
         } else {
             // Use TiB
-            ("TB", 1_073_741_824.0)
+            ("TiB", GIBI_LIMIT_F64)
         }
     }
 
@@ -324,13 +321,9 @@ pub fn convert_mem_labels(
             Some((
                 format!(
                     "{:3.0}%",
-                    match current_data.memory_harvest.mem_total_in_kib {
-                        0 => 0.0,
-                        _ =>
-                            current_data.memory_harvest.mem_used_in_kib as f64
-                                / current_data.memory_harvest.mem_total_in_kib as f64
-                                * 100.0,
-                    }
+                    current_data.memory_harvest.mem_used_in_kib as f64
+                        / current_data.memory_harvest.mem_total_in_kib as f64
+                        * 100.0
                 ),
                 {
                     let (unit, denominator) = return_unit_and_denominator_for_mem_kib(
@@ -353,24 +346,20 @@ pub fn convert_mem_labels(
             Some((
                 format!(
                     "{:3.0}%",
-                    match current_data.swap_harvest.mem_total_in_kib {
-                        0 => 0.0,
-                        _ =>
-                            current_data.swap_harvest.mem_used_in_kib as f64
-                                / current_data.swap_harvest.mem_total_in_kib as f64
-                                * 100.0,
-                    }
+                    current_data.swap_harvest.mem_used_in_kib as f64
+                        / current_data.swap_harvest.mem_total_in_kib as f64
+                        * 100.0
                 ),
                 {
-                    let (unit, numerator) = return_unit_and_denominator_for_mem_kib(
+                    let (unit, denominator) = return_unit_and_denominator_for_mem_kib(
                         current_data.swap_harvest.mem_total_in_kib,
                     );
 
                     format!(
                         "   {:.1}{}/{:.1}{}",
-                        current_data.swap_harvest.mem_used_in_kib as f64 / numerator,
+                        current_data.swap_harvest.mem_used_in_kib as f64 / denominator,
                         unit,
-                        (current_data.swap_harvest.mem_total_in_kib as f64 / numerator),
+                        (current_data.swap_harvest.mem_total_in_kib as f64 / denominator),
                         unit
                     )
                 },