diff --git a/spare-change.php b/spare-change.php
new file mode 100644
index 0000000..6102eab
--- /dev/null
+++ b/spare-change.php
@@ -0,0 +1,54 @@
+#!`which php`
+<?php
+/* 2024-03-24 Hyperling
+// Calculate the optimal amount of spare change to keep
+// at any one time which can make any cent value.
+*/
+
+echo "Got any spare change?\n";
+
+$pennies = 0; $nickels = 0; $dimes = 0; $quarters = 0;
+$maxpennies = 0; $maxnickels = 0; $maxdimes = 0; $maxquarters = 0;
+
+for ($change = 1; $change < 100; $change++) {
+	$quarters = floor($change / 25);
+	$remainder = $change % 25;
+
+	$dimes = floor($remainder / 10);
+	$remainder = $remainder % 10;
+
+	$nickels = floor($remainder / 5);
+	$remainder = $remainder % 5;
+
+	$pennies = $remainder;
+
+	if ($quarters > $maxquarters) {
+		$maxquarters = $quarters;
+		echo "Change '{$change}c' required adding another quarter, now need '$maxquarters'.\n";
+	}
+	if ($dimes > $maxdimes) {
+		$maxdimes = $dimes;
+		echo "Change '{$change}c' required adding another dime, now need '$maxdimes'.\n";
+	}
+	if ($nickels > $maxnickels) {
+		$maxnickels = $nickels;
+		echo "Change '{$change}c' required adding another nickel, now need '$maxnickels'.\n";
+	}
+	if ($pennies > $maxpennies) {
+		$maxpennies = $pennies;
+		echo "Change '{$change}c' required adding another penny, now need '$maxpennies'.\n";
+	}
+}
+
+echo "You can pay any cent value with exact change if you have $maxquarters quarter(s), $maxdimes dime(s), $maxnickels nickel(s), and $maxpennies penn(y,ies).\n";
+
+$quarters = $maxquarters * 25;
+$dimes = $maxdimes * 10;
+$nickels = $maxnickels * 5;
+$pennies = $maxpennies;
+
+$change = $quarters + $dimes + $nickels + $pennies;
+
+echo "That means you only ever need to carry {$change}c unless going to multiple locations on foot.\n";
+
+exit(0);