From c10a2adbd4e340d337bfe2ccb319f59ec8de0533 Mon Sep 17 00:00:00 2001
From: Peder Bergan <pederbe@users.noreply.github.com>
Date: Wed, 16 Sep 2026 02:47:06 +0200
Subject: [PATCH] feat: add configurable binary disk capacity units (#2236)

Enable binary disk capacity units with:

```toml
[disk]
use_binary_prefix = true
```

Or pass `--disk_use_binary_prefix` (alias `--disk-use-binary-prefix`). The CLI flag takes precedence over a false config setting. Decimal units remain the default.

Used, Free, and Total use the existing binary conversion helper. For example, 536,870,912,000 bytes changes from `537GB` to `500GiB`. Percentages, sorting by raw byte values, I/O rates, and network units retain their existing behavior.

The change passes the option from argument/config parsing through application settings and collected disk data to cell formatting. Four regression tests cover option precedence and both CLI spellings, collection-to-cell wiring, unit boundaries, missing values, percentages, I/O behavior, and sorting.
---
 .../configuration/command-line-options.md     |   6 +
 .../configuration/config-file/disk-table.md   |  10 ++
 sample_configs/default_config.toml            |   3 +
 schema/nightly/bottom.json                    |   7 ++
 src/app.rs                                    |   1 +
 src/app/data/store.rs                         |   8 +-
 src/constants.rs                              |   3 +
 src/options.rs                                |   6 +
 src/options/args.rs                           |  18 +++
 src/options/config/disk.rs                    |   4 +
 src/widgets/disk_table.rs                     | 109 +++++++++++++++++-
 11 files changed, 169 insertions(+), 6 deletions(-)

diff --git a/docs/content/configuration/command-line-options.md b/docs/content/configuration/command-line-options.md
index 42800931..bd85bd50 100644
--- a/docs/content/configuration/command-line-options.md
+++ b/docs/content/configuration/command-line-options.md
@@ -25,6 +25,12 @@ see information on these options by running `btm -h`, or run `btm --help` to dis
 |                                     | for table widgets.                                         |
 | `-d`, `--time_delta <TIME>`         | The amount of time changed upon zooming.                   |
 
+## Disk Options
+
+| Option                     | Behaviour                                                       |
+| -------------------------- | --------------------------------------------------------------- |
+| `--disk_use_binary_prefix` | Displays used, free, and total disk space with binary prefixes. |
+
 ## Process Options
 
 | Option                      | Behaviour                                                                              |
diff --git a/docs/content/configuration/config-file/disk-table.md b/docs/content/configuration/config-file/disk-table.md
index 1bac5ed3..8c8d789a 100644
--- a/docs/content/configuration/config-file/disk-table.md
+++ b/docs/content/configuration/config-file/disk-table.md
@@ -30,6 +30,16 @@ You can also set the sort order by changing `disk.sort_order` with `"Ascending"`
 sort_order = "Ascending"
 ```
 
+## Disk Space Units
+
+Disk space uses decimal prefixes (KB, MB, GB, TB) by default. To display the Used, Free, and Total columns
+with binary prefixes (KiB, MiB, GiB, TiB), enable `use_binary_prefix`:
+
+```toml
+[disk]
+use_binary_prefix = true
+```
+
 ## Show Unmounted Devices (Linux only)
 
 By default, only mounted devices are shown. To also show unmounted devices on Linux, enable `include_unmounted`:
diff --git a/sample_configs/default_config.toml b/sample_configs/default_config.toml
index 4f735ead..e79ad8b2 100644
--- a/sample_configs/default_config.toml
+++ b/sample_configs/default_config.toml
@@ -222,6 +222,9 @@
 # Disk widget configuration
 #[disk]
 
+# Whether to display used, free, and total disk space with binary prefixes (e.g. GiB instead of GB).
+#use_binary_prefix = false
+
 # The columns shown by the process widget. The following columns are supported:
 # Disk, Mount, Used, Free, Total, Used%, Free%, R/s, W/s
 #columns = ["Disk", "Mount", "Used", "Free", "Total", "Used%", "R/s", "W/s"]
diff --git a/schema/nightly/bottom.json b/schema/nightly/bottom.json
index a82a4ee6..ab988680 100644
--- a/schema/nightly/bottom.json
+++ b/schema/nightly/bottom.json
@@ -299,6 +299,13 @@
         "sort_order": {
           "description": "The default sort order. Defaults to ascending.",
           "$ref": "#/$defs/SortOrder"
+        },
+        "use_binary_prefix": {
+          "description": "Displays used, free, and total disk space with binary prefixes (e.g. GiB).\nDefaults to decimal prefixes (e.g. GB).",
+          "type": [
+            "boolean",
+            "null"
+          ]
         }
       }
     },
diff --git a/src/app.rs b/src/app.rs
index f0642fc5..5b2405c5 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -87,6 +87,7 @@ pub struct AppConfigFields {
     pub temperature_legend_position: Option<LegendPosition>,
     pub disk_io_legend_position: Option<LegendPosition>,
     pub disk_show_unmounted: bool,
+    pub disk_use_binary_prefix: bool,
     pub disk_io_graph_show_unmounted: bool,
 }
 
diff --git a/src/app/data/store.rs b/src/app/data/store.rs
index 89e21ee4..babc238f 100644
--- a/src/app/data/store.rs
+++ b/src/app/data/store.rs
@@ -214,7 +214,7 @@ impl InnerData {
         if let Some(disks) = data.disks
             && let Some(io) = data.io
         {
-            self.eat_disks(disks, io, harvested_time);
+            self.eat_disks(disks, io, harvested_time, settings.disk_use_binary_prefix);
 
             if used_widgets.use_disk_io_graph {
                 self.time_series_data.update_disk_io(
@@ -240,7 +240,10 @@ impl InnerData {
         self.last_update_time = harvested_time;
     }
 
-    fn eat_disks(&mut self, disks: Vec<DiskHarvest>, io: IoHarvest, harvested_time: Instant) {
+    fn eat_disks(
+        &mut self, disks: Vec<DiskHarvest>, io: IoHarvest, harvested_time: Instant,
+        use_binary_prefix: bool,
+    ) {
         let time_since_last_harvest = harvested_time
             .duration_since(self.last_update_time)
             .as_secs_f64();
@@ -350,6 +353,7 @@ impl InnerData {
             };
 
             self.disk_harvest.push(DiskWidgetData {
+                use_binary_prefix,
                 name: disk.name,
                 mount_point: disk.mount_point,
                 free_bytes: disk.free_space,
diff --git a/src/constants.rs b/src/constants.rs
index e39c1c94..f9553e6b 100644
--- a/src/constants.rs
+++ b/src/constants.rs
@@ -471,6 +471,9 @@ pub(crate) const CONFIG_TEXT: &str = r#"# This is a default config file for bott
 # Disk widget configuration
 #[disk]
 
+# Whether to display used, free, and total disk space with binary prefixes (e.g. GiB instead of GB).
+#use_binary_prefix = false
+
 # The columns shown by the process widget. The following columns are supported:
 # Disk, Mount, Used, Free, Total, Used%, Free%, R/s, W/s
 #columns = ["Disk", "Mount", "Used", "Free", "Total", "Used%", "R/s", "W/s"]
diff --git a/src/options.rs b/src/options.rs
index be9d90fa..407e00ca 100644
--- a/src/options.rs
+++ b/src/options.rs
@@ -542,6 +542,12 @@ pub(crate) fn init_app(args: BottomArgs, config: Config) -> Result<(App, BottomL
         temperature_legend_position,
         disk_io_legend_position,
         disk_show_unmounted,
+        disk_use_binary_prefix: args.disk.disk_use_binary_prefix
+            || config
+                .disk
+                .as_ref()
+                .and_then(|cfg| cfg.use_binary_prefix)
+                .unwrap_or(false),
         disk_io_graph_show_unmounted,
     };
 
diff --git a/src/options/args.rs b/src/options/args.rs
index 986a867d..93371694 100644
--- a/src/options/args.rs
+++ b/src/options/args.rs
@@ -73,6 +73,9 @@ pub struct BottomArgs {
     #[command(flatten)]
     pub network: NetworkArgs,
 
+    #[command(flatten)]
+    pub disk: DiskArgs,
+
     #[cfg(feature = "battery")]
     #[command(flatten)]
     pub battery: BatteryArgs,
@@ -552,6 +555,21 @@ pub struct MemoryArgs {
     pub short_gpu_names: bool,
 }
 
+/// Disk arguments/config options.
+#[derive(Args, Clone, Debug, Default)]
+#[command(next_help_heading = "Disk Options", rename_all = "snake_case")]
+pub struct DiskArgs {
+    #[arg(
+        long,
+        action = ArgAction::SetTrue,
+        help = "Displays disk space with binary prefixes.",
+        long_help = "Displays used, free, and total disk space with binary prefixes (e.g. KiB, MiB, GiB) \
+                    rather than decimal prefixes (e.g. KB, MB, GB). Defaults to decimal prefixes.",
+        alias = "disk-use-binary-prefix"
+    )]
+    pub disk_use_binary_prefix: bool,
+}
+
 /// Network arguments/config options.
 #[derive(Args, Clone, Debug, Default)]
 #[command(next_help_heading = "Network Options", rename_all = "snake_case")]
diff --git a/src/options/config/disk.rs b/src/options/config/disk.rs
index b2e095a7..03c940c5 100644
--- a/src/options/config/disk.rs
+++ b/src/options/config/disk.rs
@@ -8,6 +8,10 @@ use crate::{canvas::components::data_table::SortOrder, options::DiskWidgetColumn
 #[cfg_attr(feature = "generate_schema", derive(schemars::JsonSchema))]
 #[cfg_attr(test, serde(deny_unknown_fields), derive(PartialEq, Eq))]
 pub(crate) struct DiskConfig {
+    /// Displays used, free, and total disk space with binary prefixes (e.g. GiB).
+    /// Defaults to decimal prefixes (e.g. GB).
+    pub(crate) use_binary_prefix: Option<bool>,
+
     /// A filter over the disk names.
     pub(crate) name_filter: Option<IgnoreList>,
 
diff --git a/src/widgets/disk_table.rs b/src/widgets/disk_table.rs
index 75020258..d52d9256 100644
--- a/src/widgets/disk_table.rs
+++ b/src/widgets/disk_table.rs
@@ -10,13 +10,14 @@ use crate::{
     },
     options::config::style::Styles,
     utils::{
-        conversion::dec_bytes_per_second_string, data_units::get_decimal_bytes,
+        conversion::dec_bytes_per_second_string, data_units::convert_bytes,
         general::sort_partial_fn,
     },
 };
 
 #[derive(Clone, Debug)]
 pub struct DiskWidgetData {
+    pub use_binary_prefix: bool,
     pub name: String,
     pub mount_point: String,
     pub free_bytes: Option<u64>,
@@ -30,7 +31,7 @@ pub struct DiskWidgetData {
 impl DiskWidgetData {
     fn total_space(&self) -> Cow<'static, str> {
         if let Some(total_bytes) = self.total_bytes {
-            let converted_total_space = get_decimal_bytes(total_bytes);
+            let converted_total_space = convert_bytes(total_bytes, self.use_binary_prefix);
             format!("{:.0}{}", converted_total_space.0, converted_total_space.1).into()
         } else {
             "N/A".into()
@@ -39,7 +40,7 @@ impl DiskWidgetData {
 
     fn free_space(&self) -> Cow<'static, str> {
         if let Some(free_bytes) = self.free_bytes {
-            let converted_free_space = get_decimal_bytes(free_bytes);
+            let converted_free_space = convert_bytes(free_bytes, self.use_binary_prefix);
             format!("{:.0}{}", converted_free_space.0, converted_free_space.1).into()
         } else {
             "N/A".into()
@@ -48,7 +49,7 @@ impl DiskWidgetData {
 
     fn used_space(&self) -> Cow<'static, str> {
         if let Some(used_bytes) = self.used_bytes {
-            let converted_free_space = get_decimal_bytes(used_bytes);
+            let converted_free_space = convert_bytes(used_bytes, self.use_binary_prefix);
             format!("{:.0}{}", converted_free_space.0, converted_free_space.1).into()
         } else {
             "N/A".into()
@@ -410,3 +411,103 @@ impl DiskTableWidget {
         self.force_data_update();
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::utils::data_units::{GIBI_LIMIT, MEBI_LIMIT, TEBI_LIMIT};
+
+    fn disk(bytes: Option<u64>, use_binary_prefix: bool) -> DiskWidgetData {
+        DiskWidgetData {
+            use_binary_prefix,
+            name: "disk".into(),
+            mount_point: "/".into(),
+            free_bytes: bytes,
+            used_bytes: bytes,
+            total_bytes: bytes,
+            summed_total_bytes: bytes.map(|bytes| bytes * 2),
+            io_read_rate_bytes: bytes,
+            io_write_rate_bytes: bytes,
+        }
+    }
+
+    fn cell(data: &DiskWidgetData, column: DiskWidgetColumn) -> Cow<'static, str> {
+        data.to_cell_text(&column, NonZeroU16::new(10).unwrap())
+            .unwrap()
+    }
+
+    #[test]
+    fn disk_space_units() {
+        for (bytes, decimal, binary) in [
+            (0, "0B", "0B"),
+            (999, "999B", "999B"),
+            (1000, "1KB", "1000B"),
+            (1023, "1KB", "1023B"),
+            (1024, "1KB", "1KiB"),
+            (MEBI_LIMIT, "1MB", "1MiB"),
+            (500 * GIBI_LIMIT, "537GB", "500GiB"),
+            (TEBI_LIMIT, "1TB", "1TiB"),
+        ] {
+            for (use_binary_prefix, expected) in [(false, decimal), (true, binary)] {
+                let data = disk(Some(bytes), use_binary_prefix);
+                for column in [
+                    DiskWidgetColumn::Used,
+                    DiskWidgetColumn::Free,
+                    DiskWidgetColumn::Total,
+                ] {
+                    assert_eq!(cell(&data, column), expected);
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn disk_missing_space_and_percentages() {
+        for use_binary_prefix in [false, true] {
+            let missing = disk(None, use_binary_prefix);
+            for column in [
+                DiskWidgetColumn::Used,
+                DiskWidgetColumn::Free,
+                DiskWidgetColumn::Total,
+                DiskWidgetColumn::UsedPercent,
+                DiskWidgetColumn::FreePercent,
+                DiskWidgetColumn::IoRead,
+                DiskWidgetColumn::IoWrite,
+            ] {
+                assert_eq!(cell(&missing, column), "N/A");
+            }
+            let data = disk(Some(500 * GIBI_LIMIT), use_binary_prefix);
+            assert_eq!(cell(&data, DiskWidgetColumn::UsedPercent), "50.0%");
+            assert_eq!(cell(&data, DiskWidgetColumn::FreePercent), "50.0%");
+            assert_eq!(cell(&data, DiskWidgetColumn::IoRead), "536.9GB/s");
+            assert_eq!(cell(&data, DiskWidgetColumn::IoWrite), "536.9GB/s");
+            assert_eq!(
+                cell(
+                    &disk(Some(0), use_binary_prefix),
+                    DiskWidgetColumn::UsedPercent
+                ),
+                "N/A"
+            );
+        }
+    }
+
+    #[test]
+    fn disk_space_sorting_uses_bytes() {
+        for use_binary_prefix in [false, true] {
+            for column in [
+                DiskWidgetColumn::Used,
+                DiskWidgetColumn::Free,
+                DiskWidgetColumn::Total,
+            ] {
+                let mut data = [
+                    disk(Some(GIBI_LIMIT), use_binary_prefix),
+                    disk(Some(2 * MEBI_LIMIT), use_binary_prefix),
+                ];
+                column.sort_data(&mut data, false);
+                assert_eq!(data[0].total_bytes, Some(2 * MEBI_LIMIT));
+                column.sort_data(&mut data, true);
+                assert_eq!(data[0].total_bytes, Some(GIBI_LIMIT));
+            }
+        }
+    }
+}