diff --git a/README.md b/README.md
index 841b4f3a..6b46c70e 100644
--- a/README.md
+++ b/README.md
@@ -102,7 +102,7 @@ Options
 |---|--------|-------------|
 | **Build selection** | [`CIBW_PLATFORM`](https://cibuildwheel.readthedocs.io/en/stable/options/#platform)  | Override the auto-detected target platform |
 |   | [`CIBW_BUILD`](https://cibuildwheel.readthedocs.io/en/stable/options/#build-skip)  <br> [`CIBW_SKIP`](https://cibuildwheel.readthedocs.io/en/stable/options/#build-skip)  | Choose the Python versions to build |
-|   | [`CIBW_ARCHS_LINUX`](https://cibuildwheel.readthedocs.io/en/stable/options/#archs)  | Build non-native architectures |
+|   | [`CIBW_ARCHS`](https://cibuildwheel.readthedocs.io/en/stable/options/#archs)  | Change the architectures built on your machine by default |
 |   | [`CIBW_PROJECT_REQUIRES_PYTHON`](https://cibuildwheel.readthedocs.io/en/stable/options/#requires-python)  | Manually set the Python compatibility of your project |
 | **Build customization** | [`CIBW_ENVIRONMENT`](https://cibuildwheel.readthedocs.io/en/stable/options/#environment)  | Set environment variables needed during the build |
 |   | [`CIBW_BEFORE_ALL`](https://cibuildwheel.readthedocs.io/en/stable/options/#before-all)  | Execute a shell command on the build system before any wheels are built. |
diff --git a/cibuildwheel/__main__.py b/cibuildwheel/__main__.py
index 33a570c7..bebaf1eb 100644
--- a/cibuildwheel/__main__.py
+++ b/cibuildwheel/__main__.py
@@ -80,7 +80,7 @@ def main() -> None:
                             on this machine. Set this option to build an architecture
                             via emulation, for example, using binfmt_misc and QEMU.
                             Default: auto.
-                            Choices: auto, native, all, {}
+                            Choices: auto, auto64, auto32, native, all, {}
                         '''.format(", ".join(a.name for a in Architecture)))
     parser.add_argument('--output-dir',
                         default=os.environ.get('CIBW_OUTPUT_DIR', 'wheelhouse'),
diff --git a/cibuildwheel/architecture.py b/cibuildwheel/architecture.py
index 63e3a8bc..7aeb7be3 100644
--- a/cibuildwheel/architecture.py
+++ b/cibuildwheel/architecture.py
@@ -4,7 +4,7 @@ import re
 from enum import Enum
 from typing import Set
 
-from .typing import PlatformName, assert_never
+from .typing import Literal, PlatformName, assert_never
 
 PRETTY_NAMES = {'linux': 'Linux', 'macos': 'macOS', 'windows': 'Windows'}
 
@@ -44,6 +44,10 @@ class Architecture(Enum):
                 result.add(Architecture(platform_module.machine()))
             elif arch_str == 'all':
                 result |= Architecture.all_archs(platform=platform)
+            elif arch_str == 'auto64':
+                result |= Architecture.bitness_archs(platform=platform, bitness="64")
+            elif arch_str == 'auto32':
+                result |= Architecture.bitness_archs(platform=platform, bitness="32")
             else:
                 result.add(Architecture(arch_str))
         return result
@@ -77,6 +81,18 @@ class Architecture(Enum):
         else:
             assert_never(platform)
 
+    @staticmethod
+    def bitness_archs(platform: PlatformName, bitness: Literal['64', '32']) -> 'Set[Architecture]':
+        archs_32 = {Architecture.i686, Architecture.x86}
+        auto_archs = Architecture.auto_archs(platform)
+
+        if bitness == '64':
+            return auto_archs - archs_32
+        elif bitness == '32':
+            return auto_archs & archs_32
+        else:
+            assert_never(bitness)
+
 
 def allowed_architectures_check(
     platform: PlatformName,
diff --git a/docs/options.md b/docs/options.md
index 78ffce92..e55facaf 100644
--- a/docs/options.md
+++ b/docs/options.md
@@ -172,6 +172,8 @@ Options:
 - macOS: `x86_64` `arm64` `universal2`
 - Windows: `AMD64` `x86`
 - `auto`: The default archs for your machine - see the table below.
+    - `auto64`: Just the 64-bit auto archs
+    - `auto32`: Just the 32-bit auto archs
 - `native`: the native arch of the build machine - Matches [`platform.machine()`](https://docs.python.org/3/library/platform.html#platform.machine).
 - `all` : expands to all the architectures supported on this OS. You may want
   to use [CIBW_BUILD](#build-skip) with this option to target specific
@@ -179,18 +181,23 @@ Options:
 
 Default: `auto`
 
-| Runner | `native` | `auto`
-|---|---|---
-| Linux / Intel | `x86_64` | `x86_64` `i686`
-| Windows / Intel | `AMD64` | `AMD64` `x86`
-| macOS / Intel | `x86_64` | `x86_64`
-| macOS / Apple Silicon | `arm64` | `arm64` `universal2`
+| Runner | `native` | `auto` | `auto64` | `auto32` |
+|---|---|---|---|---|
+| Linux / Intel | `x86_64` | `x86_64` `i686` | `x86_64` | `i686` |
+| Windows / Intel | `AMD64` | `AMD64` `x86` | `AMD64` | `x86` |
+| macOS / Intel | `x86_64` | `x86_64` | `x86_64` |  |
+| macOS / Apple Silicon | `arm64` | `arm64` `universal2` | `arm64` `universal2`|  |
 
 If not listed above, `auto` is the same as `native`.
 
 [setup-qemu-action]: https://github.com/docker/setup-qemu-action
 [binfmt]: https://hub.docker.com/r/tonistiigi/binfmt
 
+Platform-specific variants also available:<br/>
+ `CIBW_ARCHS_MACOS` | `CIBW_ARCHS_WINDOWS` | `CIBW_ARCHS_LINUX`
+
+This option can also be set using the [command-line option](#command-line) `--archs`.
+
 #### Examples
 
 ```yaml
@@ -203,10 +210,6 @@ CIBW_ARCHS_MACOS: "x86_64 universal2 arm64"
 CIBW_ARCHS_LINUX: "auto aarch64"
 ```
 
-Platform-specific variants also available:<br/>
-`CIBW_ARCHS_MACOS` | `CIBW_ARCHS_WINDOWS` | `CIBW_ARCHS_LINUX`
-
-This option can also be set using the [command-line option](#command-line) `--archs`.
 
 ###  `CIBW_PROJECT_REQUIRES_PYTHON` {: #requires-python}
 > Manually set the Python compatibility of your project
diff --git a/unit_test/main_tests/main_platform_test.py b/unit_test/main_tests/main_platform_test.py
index 98bcfcdd..1b37663e 100644
--- a/unit_test/main_tests/main_platform_test.py
+++ b/unit_test/main_tests/main_platform_test.py
@@ -131,6 +131,39 @@ def test_archs_platform_native(platform, intercepted_build_args, monkeypatch):
         assert build_options.architectures == {Architecture.x86_64}
 
 
+def test_archs_platform_auto64(platform, intercepted_build_args, monkeypatch):
+    monkeypatch.setenv('CIBW_ARCHS', 'auto64')
+
+    main()
+    build_options = intercepted_build_args.args[0]
+
+    if platform == 'linux':
+        assert build_options.architectures == {Architecture.x86_64}
+    elif platform == 'windows':
+        assert build_options.architectures == {Architecture.AMD64}
+    elif platform == 'macos':
+        assert build_options.architectures == {Architecture.x86_64}
+
+
+def test_archs_platform_auto32(platform, intercepted_build_args, monkeypatch):
+    monkeypatch.setenv('CIBW_ARCHS', 'auto32')
+
+    if platform == 'macos':
+        with pytest.raises(SystemExit) as exit:
+            main()
+        assert exit.value.args == (4,)
+
+    else:
+        main()
+
+        build_options = intercepted_build_args.args[0]
+
+        if platform == 'linux':
+            assert build_options.architectures == {Architecture.i686}
+        elif platform == 'windows':
+            assert build_options.architectures == {Architecture.x86}
+
+
 def test_archs_platform_all(platform, intercepted_build_args, monkeypatch):
     monkeypatch.setenv('CIBW_ARCHS', 'all')