diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..1ee8d69
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module github.com/LeRoid-hub/humiditycalc
+
+go 1.22.2
diff --git a/internal/calc.go b/internal/calc.go
new file mode 100644
index 0000000..c767d99
--- /dev/null
+++ b/internal/calc.go
@@ -0,0 +1,26 @@
+package internal
+
+import (
+ "math"
+)
+
+// AbsoluteHumidity calculates absolute humidity in g/m³ given temperature in Celsius and relative humidity percentage.
+func AbsoluteHumidity(tempCelsius, relativeHumidity float64) float64 {
+ // Constants
+ const Mw = 18.016 // Molar mass of water vapor in g/mol
+ const R = 8.314 // Universal gas constant in J/(mol·K)
+ const A = 6.112 // Constant for saturation vapor pressure in hPa
+ const B = 17.67 // Constant for saturation vapor pressure
+ const C = 243.5 // Constant for saturation vapor pressure in Celsius
+
+ // Convert temperature from Celsius to Kelvin
+ tempKelvin := tempCelsius + 273.15
+
+ // Calculate saturation vapor pressure (in hPa) using temperature in Celsius
+ saturationVaporPressure := A * math.Exp(B*tempCelsius/(tempCelsius+C))
+
+ // Calculate absolute humidity
+ absoluteHumidity := (relativeHumidity / 100) * saturationVaporPressure * Mw / (R * tempKelvin)
+
+ return absoluteHumidity
+}
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..653b6fe
--- /dev/null
+++ b/main.go
@@ -0,0 +1,9 @@
+package main
+
+import (
+ "github.com/LeRoid-hub/humiditycalc/server"
+)
+
+func main() {
+ server.Run()
+}
diff --git a/server/server.go b/server/server.go
new file mode 100644
index 0000000..bebfcb3
--- /dev/null
+++ b/server/server.go
@@ -0,0 +1,69 @@
+package server
+
+import (
+ "fmt"
+ "net/http"
+ "strconv"
+
+ "github.com/LeRoid-hub/humiditycalc/internal"
+)
+
+// StartServer starts the HTTP server.
+func Run() {
+ http.HandleFunc("/", HandleIndex)
+
+ http.HandleFunc("/absolute-humidity", HandleAbsoluteHumidity)
+
+ http.ListenAndServe(":8080", nil)
+}
+
+func HandleIndex(w http.ResponseWriter, r *http.Request) {
+ html := `
+
+ Humidity Calculator
+
+
+ Humidity Calculator
+ Calculate absolute humidity in g/m³ given temperature in Celsius and relative humidity percentage.
+
+
+`
+ w.Write([]byte(html))
+}
+
+func HandleAbsoluteHumidity(w http.ResponseWriter, r *http.Request) {
+ // Parse query parameters
+ tempCelsius, relativeHumidity := r.URL.Query().Get("temp"), r.URL.Query().Get("rh")
+ if tempCelsius == "" || relativeHumidity == "" {
+ http.Error(w, "missing query parameters", http.StatusBadRequest)
+ return
+ }
+
+ // Convert query parameters to float64
+
+ temp, err := strconv.ParseFloat(tempCelsius, 32)
+ if err != nil {
+ http.Error(w, "invalid temperature value", http.StatusBadRequest)
+ return
+ }
+
+ rh, err := strconv.ParseFloat(relativeHumidity, 32)
+ if err != nil {
+ http.Error(w, "invalid relative humidity value", http.StatusBadRequest)
+ return
+ }
+
+ // Calculate absolute humidity
+ absoluteHumidity := internal.AbsoluteHumidity(temp, rh)
+
+ // Write response
+ w.Write([]byte(fmt.Sprintf("Absolute humidity: %.2f g/m³\n", absoluteHumidity)))
+}