diff --git a/zshrc b/zshrc
index 6449748..ba9ac67 100644
--- a/zshrc
+++ b/zshrc
@@ -630,6 +630,7 @@ alias tid="tiday"
 alias tiw="tiweek"
 alias tim="timonth"
 alias timv="timove"
+alias tiresize="tiduration"
 
 ## Functions
 ## Display tasks of today {{{
@@ -923,6 +924,65 @@ function tiend() {
 	unset tiend_confirmation tiend_time_id tiend_time_new_end
 }
 ## }}}
+## Modify the duration of a time tracking {{{
+function tiduration() {
+
+	# Define new_duration empty by default
+	tiduration_time_new_duration=""
+
+	# Verify argument
+	case "${#}" in
+		1 )
+			## Get the first arg as time ID
+			tiduration_time_id="${1}"
+			;;
+		2 )
+			## Get the first arg as time ID
+			tiduration_time_id="${1}"
+
+			## Get the second arg as new end time for this track
+			tiduration_time_new_duration="${2}"
+			;;
+		* )
+			## Ask the user to choose an ID in time tracking from the yesterday {{{
+			timew summary from yesterday :ids || return 0
+
+			printf '%b' "Enter the ${MAGENTAB}ID${RESET} of the time tracking to modify : "
+			read -r tiduration_time_id
+			## }}}
+			;;
+	esac
+
+	# If no time tracking exists with this ID, exit function {{{
+	if ! timew summary :year :ids | grep --quiet -- " @${tiduration_time_id} "; then
+		printf '%b' "No available time tracking in the last year with ${REDB}${tiduration_time_id}${RESET} ID."
+		return 1
+	fi
+	# }}}
+
+	# Get time tracking's description from all time tracking of this year
+	local tiduration_time_desc=$(timew summary :year :ids | sed -n "s/.*@\(${tiduration_time_id} .*\)/\1/p" | sed 's/   */ − /g')
+
+	# Check or ask for new end time {{{
+	if [ -z "${tiduration_time_new_duration}" ]; then
+			printf '%b' "Enter the ${MAGENTAB}new duration${RESET} (eg. 25mins, 1hour…) for this time tracking : "
+			read -r tiduration_time_new_duration
+	fi
+	# }}}
+
+	printf '%b' "Change duration of \"${MAGENTAB}${tiduration_time_desc}${RESET}\" to ${REDB}=> ${tiduration_time_new_duration} <=${RESET} [Y/n] ? "
+	read -r tiduration_confirmation
+
+	# Check confirmation
+	if printf -- '%s' "${tiduration_confirmation:=y}" | grep --quiet --word-regexp -- "y"; then
+		timew resize @"${tiduration_time_id}" "${tiduration_time_new_duration}" || return 0
+		printf '%b' "Duration of ${tiduration_time_desc} is now ${tiduration_time_new_duration}."
+	fi
+
+	# Unset defined variables
+	unset tiduration_confirmation tiduration_time_id tiduration_time_new_duration
+}
+## }}}
 ## Move a time tracking {{{
 function timove() {