diff --git a/README.md b/README.md
index 009725a..60a130c 100644
--- a/README.md
+++ b/README.md
@@ -196,8 +196,8 @@ Time worked on project: 00:00:06
 Tracking data saved to file /home/patrick/track/2021-12
 ~~~
 
-#### `at <seconds> [<Project Name>/][<Task Name>]`
-Manually adds `<seconds>` seconds to task's work time. \
+#### `at <time>[s/m/h] [<Project Name>/][<Task Name>]`
+Manually adds `<time>` to task's work time. If `<time>` is followed by `m` or `h`, `<time>` is interpreted as minutes / hours. With `s` or without a postfix, time is interpreted as seconds. \
 If the optional parameter `<Task Name>` is present, the time is beeing added to the Task with name `<Task Name>` of the currently active project.\
 If also the optional parameter `<Project Name>` is present, the time is beeing added to the task with name `<Task Name>` of project `<Project Name>`.
 
diff --git a/src/string_utils.cpp b/src/string_utils.cpp
index 00e0f47..f885ebf 100644
--- a/src/string_utils.cpp
+++ b/src/string_utils.cpp
@@ -1,4 +1,5 @@
 #include <string>
+#include <iostream>
 #include "string_utils.h"
 
 // replaces white spaces by underscores, used for readline completion
@@ -32,3 +33,45 @@ bool is_num(const std::string &str){
     }
     return true;
 }
+
+// convert string "X[s,m,h]" to seconds
+int string2sec(std::string str){
+    int seconds = 0;
+    size_t place_of_hour = str.find("h");
+    size_t place_of_minute = str.find("m");
+    size_t place_of_second = str.find("s");
+    std::string timestr=str;
+    int factor = 1;
+    
+    if (is_num(str)){
+        seconds = std::stoi(str);
+        return seconds;
+    }else if (place_of_hour < place_of_minute){
+        if (place_of_hour < place_of_second){
+            //seconds = std::stoi(str.substr(0,place_of_hour))*3600;
+            timestr = str.substr(0,place_of_hour);
+            factor = 3600;
+        }else {
+            //seconds = std::stoi(str.substr(0,place_of_second));
+            timestr = str.substr(0,place_of_second);
+        }
+    }else if (place_of_minute < place_of_hour){
+        if (place_of_minute < place_of_second){
+            //seconds = std::stoi(str.substr(0,place_of_minute))*60;
+            timestr = str.substr(0,place_of_minute);
+            factor = 60;
+        }else{
+            //seconds = std::stoi(str.substr(0,place_of_second));
+            timestr = str.substr(0,place_of_second);
+        }
+    }else{
+        timestr = str.substr(0,place_of_second);
+    }
+
+    if (is_num(timestr) && timestr.length() > 0){
+        seconds = std::stoi(timestr)*factor;
+    } else{
+            std::cout << "Wrong format of time string. Allowed: <X> OR <X>s OR <X>m OR <X>h." << std::endl;
+    }
+    return seconds;
+}
diff --git a/src/string_utils.h b/src/string_utils.h
index 460b860..1597238 100644
--- a/src/string_utils.h
+++ b/src/string_utils.h
@@ -6,4 +6,5 @@ std::string trim(const std::string &str);
 std::string space_to_underscore(std::string str);
 std::string underscore_to_space(std::string str);
 bool is_num(const std::string &str);
+int string2sec(std::string str);
 #endif
diff --git a/src/tt.h b/src/tt.h
index b11dadb..d63635c 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -3,7 +3,7 @@
 
 #include <string>
 
-#define TT_VERSION 1.0.1
+#define TT_VERSION 1.1.0
 
 // global variables:
 extern std::string user_name;
diff --git a/src/ui.cpp b/src/ui.cpp
index acddf69..8fb41a1 100644
--- a/src/ui.cpp
+++ b/src/ui.cpp
@@ -129,18 +129,21 @@ void parse_input(std::string input, ProjectList *proj_list){
             command_re(argument.substr(0,first_name_end),argument.substr(first_name_end+1),proj_list);
         }
     }else if (command == "at"){
+        int seconds = 0;
         if (command_end == std::string::npos){
             std::cout << "add time: please specify time to add and task name [optional]." << std::endl;
         }else{
             // only 1 argument
-            if(is_num(trim(argument))){
-                command_at("",stoi(argument),proj_list);
+            if(argument.find(" ") == std::string::npos){
+                seconds = string2sec(argument);
+                command_at("",seconds,proj_list);
             }else{
                 size_t start_of_name = argument.find(" ");
                 std::string wtime_str = argument.substr(0,start_of_name);
                 std::string task_name = argument.substr(start_of_name+1);
-                if (is_num(wtime_str) && start_of_name != std::string::npos){
-                    command_at(task_name,stoi(wtime_str),proj_list);
+                seconds = string2sec(wtime_str);
+                if (start_of_name != std::string::npos){
+                    command_at(task_name,seconds,proj_list);
                 }else{
                     std::cout << "add time: please specify time to add and task name [optional]." << std::endl;
                 }
@@ -149,18 +152,21 @@ void parse_input(std::string input, ProjectList *proj_list){
         }
         
     }else if (command == "rt"){
+        int seconds = 0;
         if (command_end == std::string::npos){
             std::cout << "remove time: please specify time to remove and task name [optional]." << std::endl;
         }else{
             // only 1 argument
-            if(is_num(trim(argument))){
-                command_rt("",stoi(argument),proj_list);
+            if(argument.find(" ") == std::string::npos){
+                seconds = string2sec(argument);
+                command_rt("",seconds,proj_list);
             }else{
                 size_t start_of_name = argument.find(" ");
                 std::string wtime_str = argument.substr(0,start_of_name);
                 std::string task_name = argument.substr(start_of_name+1);
-                if (is_num(wtime_str) && start_of_name != std::string::npos){
-                    command_rt(task_name,stoi(wtime_str),proj_list);
+                seconds = string2sec(wtime_str);
+                if (start_of_name != std::string::npos){
+                    command_rt(task_name,seconds,proj_list);
                 }else{
                     std::cout << "remove time: please specify time to remove and task name [optional]." << std::endl;
                 }