diff --git a/utils.js b/utils.js
new file mode 100644
index 0000000..89d5ba9
--- /dev/null
+++ b/utils.js
@@ -0,0 +1,12 @@
+function observed_volume(FoV_Width, FoV_Height, Sample_Size, Slip_Width, Slip_Height){
+  // Slip dimensions in mm - Sample Size in uL:
+  // uL / mm*mm  -> 10^9 um³ / 10^6 um²
+  // 10^9 um³ / 10^12 um² = 10^3 um
+  let h = (Sample_Size / Slip_Width*Slip_Height)*Math.pow(10,3);
+
+  // observed volume = h * Area FoV [um³]
+  // 1 um³ = 10^-9 uL
+  let observed_volume = h * FoV_Width * FoV_Height * Math.pow(10,-9);
+
+  return observed_volume
+}