diff --git a/kitty/fonts.c b/kitty/fonts.c
index 76ba64246..dc5b295f1 100644
--- a/kitty/fonts.c
+++ b/kitty/fonts.c
@@ -331,6 +331,20 @@ python_send_to_gpu(FONTS_DATA_HANDLE fg, unsigned int x, unsigned int y, unsigne
     }
 }
 
+static void
+adjust_metric(unsigned int *metric, float adj, AdjustmentUnit unit, double dpi) {
+    if (adj == 0.f) return;
+    int a = 0;
+    switch (unit) {
+        case POINT:
+            a = ((long)round((adj * (dpi / 72.0)))); break;
+        case PERCENT:
+            *metric = (int)roundf((fabsf(adj) * (float)*metric) / 100.f); return;
+        case PIXEL:
+            a = (int)roundf(adj); break;
+    }
+    *metric = (a < 0 && -a > (int)*metric) ? 0 : *metric + a;
+}
 
 static void
 calc_cell_metrics(FontGroup *fg) {
@@ -358,6 +372,11 @@ calc_cell_metrics(FontGroup *fg) {
 #undef MIN_WIDTH
 #undef MIN_HEIGHT
 #undef MAX_DIM
+
+#define A(which, dpi) adjust_metric(&which, OPT(which).val, OPT(which).unit, fg->logical_dpi_##dpi);
+    A(underline_thickness, y); A(underline_position, y); A(strikethrough_thickness, y); A(strikethrough_position, y);
+#undef A
+
     underline_position = MIN(cell_height - 1, underline_position);
     // ensure there is at least a couple of pixels available to render styled underlines
     while (underline_position > baseline + 1 && cell_height - underline_position < 2) underline_position--;
diff --git a/kitty/options/to-c.h b/kitty/options/to-c.h
index 82a7efa67..ba2ed1820 100644
--- a/kitty/options/to-c.h
+++ b/kitty/options/to-c.h
@@ -120,11 +120,8 @@ parse_font_mod_size(PyObject *val, float *sz, AdjustmentUnit *unit) {
     PyObject *mv = PyObject_GetAttrString(val, "mod_value");
     if (mv) {
         *sz = PyFloat_AsFloat(PyTuple_GET_ITEM(mv, 0));
-        switch (PyLong_AsLong(PyTuple_GET_ITEM(mv, 1))) {
-            case 0: *unit = POINT; break;
-            case 1: *unit = PIXEL; break;
-            case 2: *unit = PERCENT; break;
-        }
+        long u = PyLong_AsLong(PyTuple_GET_ITEM(mv, 1));
+        switch (u) { case POINT: case PERCENT: case PIXEL: *unit = u; break; }
     }
 }
 
diff --git a/kitty/state.h b/kitty/state.h
index 0f911a76a..e7dbb8019 100644
--- a/kitty/state.h
+++ b/kitty/state.h
@@ -21,7 +21,7 @@ typedef struct {
     size_t len;
 } UrlPrefix;
 
-typedef enum AdjustmentUnit { POINT, PERCENT, PIXEL } AdjustmentUnit;
+typedef enum AdjustmentUnit { POINT = 0, PERCENT = 1, PIXEL = 2 } AdjustmentUnit;
 
 typedef struct {
     monotonic_t visual_bell_duration, cursor_blink_interval, cursor_stop_blinking_after, mouse_hide_wait, click_interval;