diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index d17f81036..3ab9d72f3 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -4708,6 +4708,27 @@ system and gives an overview of their function and contents.
       See the :term:`MACHINE` variable for additional
       information.
 
+   :term:`INITRAMFS_MAXSIZE`
+      Defines the maximum allowed size of the initramfs image in kilobytes.
+      The build will fail if the initramfs image size is larger than the value of this variable.
+
+      The initramfs image size undergoes several calculation steps before it is compared with ``INITRAMFS_MAXSIZE``.
+      In the first step, the size of the directory pointed to by ``IMAGE_ROOTFS`` is calculated.
+      In the second step, the result from the first step is multiplied by ``IMAGE_OVERHEAD_FACTOR``.
+      In the third step, the result from the second step is compared with ``IMAGE_ROOTFS_SIZE``.
+      The larger value of these is added to ``IMAGE_ROOTFS_EXTRA_SPACE``.
+      In the fourth step, the result from the third step is checked for a decimal part. If it has one,
+      it is rounded up to the next integer. If it does not, it is simply converted into an integer.
+      In the fifth step, the ``IMAGE_ROOTFS_ALIGNMENT`` is added to the result from the fourth step
+      and the value "-1" is subtracted.
+      In the sixth step, the remainder of the division between the result from the fifth step
+      and ``IMAGE_ROOTFS_ALIGNMENT`` is subtracted from the result of the fifth step.
+      In this way, the result from the fourth step is rounded up to the nearest multiple of ``IMAGE_ROOTFS_ALIGNMENT``.
+
+      Thus, ``INITRAMFS_MAXSIZE`` is compared with the result of the above calculations
+      and is independent of the final image type.
+      A default value for ``INITRAMFS_MAXSIZE`` is set in ``meta/conf/bitbake.conf``.
+
    :term:`INITRAMFS_MULTICONFIG`
       Defines the multiconfig to create a multiconfig dependency to be used by
       the :ref:`ref-classes-kernel` class.