diff --git a/R/docx_add.R b/R/docx_add.R
index 6e0a919e..11f6b813 100644
--- a/R/docx_add.R
+++ b/R/docx_add.R
@@ -20,23 +20,34 @@ body_add_break <- function(x, pos = "after") {
 #' @inheritParams body_add_break
 #' @param src image filename, the basename of the file must not contain any blank.
 #' @param style paragraph style
-#' @param width height in inches
-#' @param height height in inches
+#' @param width,height image size in units expressed by the unit argument.
+#' Defaults to "in"ches.
+#' @param unit One of the following units in which the width and height
+#' arguments are expressed: "in", "cm" or "mm".
 #' @examples
 #' doc <- read_docx()
 #'
 #' img.file <- file.path(R.home("doc"), "html", "logo.jpg")
 #' if (file.exists(img.file)) {
 #'   doc <- body_add_img(x = doc, src = img.file, height = 1.06, width = 1.39)
+#'
+#'   # Set the unit in which the width and height arguments are expressed
+#'   doc <- body_add_img(
+#'     x = doc, src = img.file,
+#'     height = 2.69, width = 3.53,
+#'     unit = "cm"
+#'   )
 #' }
 #'
 #' print(doc, target = tempfile(fileext = ".docx"))
 #' @family functions for adding content
-body_add_img <- function(x, src, style = NULL, width, height, pos = "after") {
+body_add_img <- function(x, src, style = NULL, width, height, unit = "in", pos = "after") {
   if (is.null(style)) {
     style <- x$default_styles$paragraph
   }
 
+  unit <- check_unit(unit, c("in", "cm", "mm"))
+
   file_type <- gsub("(.*)(\\.[a-zA-Z0-0]+)$", "\\2", src)
 
   if (file_type %in% ".svg") {
@@ -55,7 +66,7 @@ body_add_img <- function(x, src, style = NULL, width, height, pos = "after") {
 
   style_id <- get_style_id(data = x$styles, style = style, type = "paragraph")
 
-  ext_img <- external_img(new_src, width = width, height = height)
+  ext_img <- external_img(new_src, width = width, height = height, unit = unit)
   xml_elt <- runs_to_p_wml(ext_img, add_ns = TRUE, style_id = style_id)
 
   body_add_xml(x = x, str = xml_elt, pos = pos)
@@ -112,8 +123,10 @@ body_add_docx <- function(x, src, pos = "after") {
 #' @inheritParams body_add_break
 #' @param value ggplot object
 #' @param style paragraph style
-#' @param width height in inches
-#' @param height height in inches
+#' @param width,height plot size in units expressed by the unit argument.
+#' Defaults to a width of 6 and a height of 5 "in"ches.
+#' @param unit One of the following units in which the width and height
+#' arguments are expressed: "in", "cm" or "mm".
 #' @param res resolution of the png image in ppi
 #' @param scale Multiplicative scaling factor, same as in ggsave
 #' @param pos where to add the new element relative to the cursor,
@@ -129,24 +142,37 @@ body_add_docx <- function(x, src, pos = "after") {
 #'
 #'   if (capabilities(what = "png")) {
 #'     doc <- body_add_gg(doc, value = gg_plot, style = "centered")
+#'
+#'     # Set the unit in which the width and height arguments are expressed
+#'     doc <- body_add_gg(doc, value = gg_plot, style = "centered", unit = "cm")
 #'   }
 #'
 #'   print(doc, target = tempfile(fileext = ".docx"))
 #' }
 #' @family functions for adding content
 #' @importFrom ragg agg_png
-body_add_gg <- function(x, value, width = 6, height = 5, res = 300, style = "Normal", scale = 1, pos = "after", ...) {
+body_add_gg <- function(x, value, width = 6, height = 5, unit = "in", res = 300, style = "Normal", scale = 1, pos = "after", ...) {
   if (!requireNamespace("ggplot2")) {
     stop("package ggplot2 is required to use this function")
   }
 
   stopifnot(inherits(value, "gg"))
+
+  if ("units" %in% names(list(...))) {
+    cli::cli_abort(
+      c("Found a {.arg units} argument. Did you mean {.arg unit}?")
+    )
+  }
+
+  unit <- check_unit(unit, c("in", "cm", "mm"))
+
+
   file <- tempfile(fileext = ".png")
-  agg_png(filename = file, width = width, height = height, scaling = scale, units = "in", res = res, background = "transparent", ...)
+  agg_png(filename = file, width = width, height = height, scaling = scale, units = unit, res = res, background = "transparent", ...)
   print(value)
   dev.off()
   on.exit(unlink(file))
-  body_add_img(x, src = file, style = style, width = width, height = height, pos = pos)
+  body_add_img(x, src = file, style = style, width = width, height = height, pos = pos, unit = unit)
 }
 
 
@@ -364,8 +390,10 @@ body_add_toc <- function(x, level = 3, pos = "after", style = NULL, separator =
 #' @inheritParams body_add_break
 #' @param value plot instructions, see [plot_instr()].
 #' @param style paragraph style
-#' @param width height in inches
-#' @param height height in inches
+#' @param width,height plot size in units expressed by the unit argument.
+#' Defaults to a width of 6 and a height of 5 "in"ches.
+#' @param unit One of the following units in which the width and height
+#' arguments are expressed: "in", "cm" or "mm".
 #' @param res resolution of the png image in ppi
 #' @param pos where to add the new element relative to the cursor,
 #' one of "after", "before", "on".
@@ -375,21 +403,25 @@ body_add_toc <- function(x, level = 3, pos = "after", style = NULL, separator =
 #' doc <- read_docx()
 #'
 #' if (capabilities(what = "png")) {
-#'   doc <- body_add_plot(doc,
-#'     value = plot_instr(
+#'   p <- plot_instr(
 #'       code = {
 #'         barplot(1:5, col = 2:6)
 #'       }
-#'     ),
-#'     style = "centered"
-#'   )
+#'     )
+#'
+#'   doc <- body_add_plot(doc, value = p, style = "centered")
+#'
+#'   # Set the unit in which the width and height arguments are expressed
+#'   doc <- body_add_plot(doc, value = p, style = "centered", unit = "cm")
 #' }
 #'
 #' print(doc, target = tempfile(fileext = ".docx"))
 #' @family functions for adding content
-body_add_plot <- function(x, value, width = 6, height = 5, res = 300, style = "Normal", pos = "after", ...) {
+body_add_plot <- function(x, value, width = 6, height = 5, unit = "in", res = 300, style = "Normal", pos = "after", ...) {
+  unit <- check_unit(unit, c("in", "cm", "mm"))
+
   file <- tempfile(fileext = ".png")
-  agg_png(filename = file, width = width, height = height, units = "in", res = res, background = "transparent", ...)
+  agg_png(filename = file, width = width, height = height, units = unit, res = res, background = "transparent", ...)
   tryCatch(
     {
       eval(value$code)
@@ -399,7 +431,7 @@ body_add_plot <- function(x, value, width = 6, height = 5, res = 300, style = "N
     }
   )
   on.exit(unlink(file))
-  body_add_img(x, src = file, style = style, width = width, height = height, pos = pos)
+  body_add_img(x, src = file, style = style, width = width, height = height, unit = unit, pos = pos)
 }
 
 
@@ -886,30 +918,36 @@ body_add.run_columnbreak <- function(x, value, style = NULL, ...) {
 
 #' @export
 #' @describeIn body_add add a ggplot object.
-#' @param width height in inches
-#' @param height height in inches
+#' @param width,height plot size in units expressed by the unit argument.
+#' Defaults to a width of 6 and a height of 5 "in"ches.
+#' @param unit One of the following units in which the width and height
+#' arguments are expressed: "in", "cm" or "mm".
 #' @param res resolution of the png image in ppi
 #' @param scale Multiplicative scaling factor, same as in ggsave
-body_add.gg <- function(x, value, width = 6, height = 5, res = 300, style = "Normal", scale = 1, ...) {
+body_add.gg <- function(x, value, width = 6, height = 5, unit = "in", res = 300, style = "Normal", scale = 1, ...) {
   if (!requireNamespace("ggplot2")) {
     stop("package ggplot2 is required to use this function")
   }
 
+  unit <- check_unit(unit, c("in", "cm", "mm"))
+
   file <- tempfile(fileext = ".png")
-  agg_png(filename = file, width = width, height = height, units = "in", res = res, scaling = scale, background = "transparent", ...)
+  agg_png(filename = file, width = width, height = height, units = unit, res = res, scaling = scale, background = "transparent", ...)
   print(value)
   dev.off()
   on.exit(unlink(file))
 
-  value <- external_img(src = file, width = width, height = height)
+  value <- external_img(src = file, width = width, height = height, unit = unit)
   body_add(x, value, style = style)
 }
 
 #' @export
 #' @describeIn body_add add a base plot with a [plot_instr] object.
-body_add.plot_instr <- function(x, value, width = 6, height = 5, res = 300, style = "Normal", ...) {
+body_add.plot_instr <- function(x, value, width = 6, height = 5, unit = "in", res = 300, style = "Normal", ...) {
+  unit <- check_unit(unit, c("in", "cm", "mm"))
+
   file <- tempfile(fileext = ".png")
-  agg_png(filename = file, width = width, height = height, units = "in", res = res, scaling = 1, background = "transparent", ...)
+  agg_png(filename = file, width = width, height = height, units = unit, res = res, scaling = 1, background = "transparent", ...)
   tryCatch(
     {
       eval(value$code)
@@ -920,12 +958,11 @@ body_add.plot_instr <- function(x, value, width = 6, height = 5, res = 300, styl
   )
   on.exit(unlink(file))
 
-  value <- external_img(src = file, width = width, height = height)
+  value <- external_img(src = file, width = width, height = height, unit = unit)
 
   body_add(x, value, style = style)
 }
 
-
 #' @export
 #' @describeIn body_add pour content of an external docx file with with a [block_pour_docx] object
 body_add.block_pour_docx <- function(x, value, ...) {
diff --git a/R/utils.R b/R/utils.R
index cf69f6dc..0200f5c2 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -334,6 +334,24 @@ stop_if_not_rpptx <- function(x, arg = NULL) {
   stop_if_not_class(x, "rpptx", arg)
 }
 
+check_unit <- function(unit, choices, several.ok = FALSE) {
+  if (!several.ok && length(unit) != 1) {
+    cli::cli_abort(
+      c("{.arg unit} is not length 1.",
+        "x" = "{.arg unit} must be {.emph a string}."
+      )
+    )
+  }
+  if (!unit %in% choices) {
+    cli::cli_abort(
+      c("{.arg unit} should be one of {.or {choices}}.",
+        "x" = "{.arg unit} was {.emph {unit}\"}."
+      )
+    )
+  }
+
+  unit
+}
 
 # htmlEscapeCopy ----
 
diff --git a/man/body_add.Rd b/man/body_add.Rd
index c1833ec5..95e99113 100644
--- a/man/body_add.Rd
+++ b/man/body_add.Rd
@@ -56,13 +56,23 @@ body_add(x, value, ...)
   value,
   width = 6,
   height = 5,
+  unit = "in",
   res = 300,
   style = "Normal",
   scale = 1,
   ...
 )
 
-\method{body_add}{plot_instr}(x, value, width = 6, height = 5, res = 300, style = "Normal", ...)
+\method{body_add}{plot_instr}(
+  x,
+  value,
+  width = 6,
+  height = 5,
+  unit = "in",
+  res = 300,
+  style = "Normal",
+  ...
+)
 
 \method{body_add}{block_pour_docx}(x, value, ...)
 
@@ -93,9 +103,11 @@ argument \code{path} from \link{read_docx}).}
 \item{alignment}{columns alignement, argument length must match with columns length,
 values must be "l" (left), "r" (right) or "c" (center).}
 
-\item{width}{height in inches}
+\item{width, height}{plot size in units expressed by the unit argument.
+Defaults to a width of 6 and a height of 5 "in"ches.}
 
-\item{height}{height in inches}
+\item{unit}{One of the following units in which the width and height
+arguments are expressed: "in", "cm" or "mm".}
 
 \item{res}{resolution of the png image in ppi}
 
diff --git a/man/body_add_gg.Rd b/man/body_add_gg.Rd
index 92e3cb8a..12dc5f56 100644
--- a/man/body_add_gg.Rd
+++ b/man/body_add_gg.Rd
@@ -9,6 +9,7 @@ body_add_gg(
   value,
   width = 6,
   height = 5,
+  unit = "in",
   res = 300,
   style = "Normal",
   scale = 1,
@@ -21,9 +22,11 @@ body_add_gg(
 
 \item{value}{ggplot object}
 
-\item{width}{height in inches}
+\item{width, height}{plot size in units expressed by the unit argument.
+Defaults to a width of 6 and a height of 5 "in"ches.}
 
-\item{height}{height in inches}
+\item{unit}{One of the following units in which the width and height
+arguments are expressed: "in", "cm" or "mm".}
 
 \item{res}{resolution of the png image in ppi}
 
@@ -48,6 +51,9 @@ if (require("ggplot2")) {
 
   if (capabilities(what = "png")) {
     doc <- body_add_gg(doc, value = gg_plot, style = "centered")
+
+    # Set the unit in which the width and height arguments are expressed
+    doc <- body_add_gg(doc, value = gg_plot, style = "centered", unit = "cm")
   }
 
   print(doc, target = tempfile(fileext = ".docx"))
diff --git a/man/body_add_img.Rd b/man/body_add_img.Rd
index aea9934d..65a248c3 100644
--- a/man/body_add_img.Rd
+++ b/man/body_add_img.Rd
@@ -4,7 +4,7 @@
 \alias{body_add_img}
 \title{Add an image in a 'Word' document}
 \usage{
-body_add_img(x, src, style = NULL, width, height, pos = "after")
+body_add_img(x, src, style = NULL, width, height, unit = "in", pos = "after")
 }
 \arguments{
 \item{x}{an rdocx object}
@@ -13,9 +13,11 @@ body_add_img(x, src, style = NULL, width, height, pos = "after")
 
 \item{style}{paragraph style}
 
-\item{width}{height in inches}
+\item{width, height}{image size in units expressed by the unit argument.
+Defaults to "in"ches.}
 
-\item{height}{height in inches}
+\item{unit}{One of the following units in which the width and height
+arguments are expressed: "in", "cm" or "mm".}
 
 \item{pos}{where to add the new element relative to the cursor,
 one of "after", "before", "on".}
@@ -29,6 +31,13 @@ doc <- read_docx()
 img.file <- file.path(R.home("doc"), "html", "logo.jpg")
 if (file.exists(img.file)) {
   doc <- body_add_img(x = doc, src = img.file, height = 1.06, width = 1.39)
+
+  # Set the unit in which the width and height arguments are expressed
+  doc <- body_add_img(
+    x = doc, src = img.file,
+    height = 2.69, width = 3.53,
+    unit = "cm"
+  )
 }
 
 print(doc, target = tempfile(fileext = ".docx"))
diff --git a/man/body_add_plot.Rd b/man/body_add_plot.Rd
index 55b2d342..8b443fea 100644
--- a/man/body_add_plot.Rd
+++ b/man/body_add_plot.Rd
@@ -9,6 +9,7 @@ body_add_plot(
   value,
   width = 6,
   height = 5,
+  unit = "in",
   res = 300,
   style = "Normal",
   pos = "after",
@@ -20,9 +21,11 @@ body_add_plot(
 
 \item{value}{plot instructions, see \code{\link[=plot_instr]{plot_instr()}}.}
 
-\item{width}{height in inches}
+\item{width, height}{plot size in units expressed by the unit argument.
+Defaults to a width of 6 and a height of 5 "in"ches.}
 
-\item{height}{height in inches}
+\item{unit}{One of the following units in which the width and height
+arguments are expressed: "in", "cm" or "mm".}
 
 \item{res}{resolution of the png image in ppi}
 
@@ -40,14 +43,16 @@ Add a plot as a png image into an rdocx object.
 doc <- read_docx()
 
 if (capabilities(what = "png")) {
-  doc <- body_add_plot(doc,
-    value = plot_instr(
+  p <- plot_instr(
       code = {
         barplot(1:5, col = 2:6)
       }
-    ),
-    style = "centered"
-  )
+    )
+
+  doc <- body_add_plot(doc, value = p, style = "centered")
+
+  # Set the unit in which the width and height arguments are expressed
+  doc <- body_add_plot(doc, value = p, style = "centered", unit = "cm")
 }
 
 print(doc, target = tempfile(fileext = ".docx"))
diff --git a/man/body_replace_gg_at_bkm.Rd b/man/body_replace_gg_at_bkm.Rd
index 72f14b11..25114ab6 100644
--- a/man/body_replace_gg_at_bkm.Rd
+++ b/man/body_replace_gg_at_bkm.Rd
@@ -38,9 +38,8 @@ body_replace_plot_at_bkm(
 \item{value}{a ggplot object for body_replace_gg_at_bkm() or a set plot instructions
 body_replace_plot_at_bkm(), see plot_instr().}
 
-\item{width}{height in inches}
-
-\item{height}{height in inches}
+\item{width, height}{plot size in units expressed by the unit argument.
+Defaults to a width of 6 and a height of 5 "in"ches.}
 
 \item{res}{resolution of the png image in ppi}
 
diff --git a/tests/testthat/test-docx-add.R b/tests/testthat/test-docx-add.R
index 2313aa81..3bd6848a 100644
--- a/tests/testthat/test-docx-add.R
+++ b/tests/testthat/test-docx-add.R
@@ -4,6 +4,45 @@ getncheck <- function(x, str){
   child_
 }
 
+plot_with_unit_and_check <- function(value, body_add_fun, width = 6, height = 5, ...) {
+  .in_to_emu <- 914400
+  .cm_to_emu <- 360000
+  .mm_to_emu <- 36000
+
+  x <- read_docx()
+  x <- body_add_fun(x, value, width = width, height = height, ... )
+  x <- body_add_fun(x, value, unit = "in", width = width, height = height, ... )
+  x <- body_add_fun(x, value, unit = "cm", width = width, height = height,... )
+  x <- body_add_fun(x, value, unit = "mm", width = width, height = height,... )
+  x <- cursor_end(x)
+  node <- docx_current_block_xml(x)
+
+  expect_equal(
+    as.numeric(
+      xml_attr(xml_find_all(node, "//wp:extent"), "cx")
+    ) /  c(.in_to_emu, .in_to_emu, .cm_to_emu, .mm_to_emu),
+    rep(width, 4)
+  )
+  expect_equal(
+    as.numeric(
+      xml_attr(xml_find_all(node, "//wp:extent"), "cy")
+    ) /   c(.in_to_emu, .in_to_emu, .cm_to_emu, .mm_to_emu),
+    rep(height, 4)
+  )
+  # Non valid unit
+  expect_error(
+    body_add_fun(x, value, unit = "px", ... )
+  )
+  # Has "units="
+  expect_error(
+    body_add_fun(x, value, units = "cm", ... )
+  )
+  # Has multiple units
+  expect_error(
+    body_add_fun(x, value, unit = c("cm", "in", "mm"), ... )
+  )
+}
+
 test_that("body_add_break", {
   x <- read_docx()
   x <- body_add_break(x)
@@ -117,6 +156,14 @@ test_that("body_add_img", {
   getncheck(node, "w:r/w:drawing")
 })
 
+test_that("body_add_img with units", {
+
+  img.file <- file.path( R.home("doc"), "html", "logo.jpg" )
+
+  plot_with_unit_and_check(img.file, body_add_img, height = 2.69, width = 3.53)
+
+})
+
 test_that("external_img add", {
   img.file <- file.path( R.home("doc"), "html", "logo.jpg" )
   x <- read_docx()
@@ -130,6 +177,7 @@ test_that("external_img add", {
   getncheck(node, "w:r/w:drawing")
 })
 
+
 test_that("ggplot add", {
   testthat::skip_if_not(requireNamespace("ggplot2", quietly = TRUE))
   library("ggplot2")
@@ -143,6 +191,29 @@ test_that("ggplot add", {
   getncheck(node, "w:r/w:drawing")
 })
 
+test_that("ggplot add with unit", {
+  testthat::skip_if_not(requireNamespace("ggplot2", quietly = TRUE))
+  library("ggplot2")
+
+  gg_plot <- ggplot(data = iris ) +
+    geom_point(mapping = aes(Sepal.Length, Petal.Length))
+
+  plot_with_unit_and_check(gg_plot, body_add_gg)
+  plot_with_unit_and_check(gg_plot, body_add)
+})
+
+test_that("plot add with unit", {
+  base_plot <- plot_instr(
+    code = {
+      barplot(1:5, col = 2:6)
+    }
+  )
+
+  # Base plot errors for "mm" with default pointsize of 12.
+  plot_with_unit_and_check(base_plot, body_add_plot, pointsize = 1)
+  plot_with_unit_and_check(base_plot, body_add, pointsize = 1)
+})
+
 test_that("fpar add", {
   bold_face <- shortcuts$fp_bold(font.size = 20)
   bold_redface <- update(bold_face, color = "red")