diff --git a/src/app/Console/Commands/WalletUntil.php b/src/app/Console/Commands/WalletUntil.php
new file mode 100644
--- /dev/null
+++ b/src/app/Console/Commands/WalletUntil.php
@@ -0,0 +1,50 @@
+<?php
+
+namespace App\Console\Commands;
+
+use Illuminate\Console\Command;
+
+class WalletUntil extends Command
+{
+    /**
+     * The name and signature of the console command.
+     *
+     * @var string
+     */
+    protected $signature = 'wallet:until {wallet}';
+
+    /**
+     * The console command description.
+     *
+     * @var string
+     */
+    protected $description = 'Show until when the balance on a wallet lasts.';
+
+    /**
+     * Create a new command instance.
+     *
+     * @return void
+     */
+    public function __construct()
+    {
+        parent::__construct();
+    }
+
+    /**
+     * Execute the console command.
+     *
+     * @return mixed
+     */
+    public function handle()
+    {
+        $wallet = \App\Wallet::find($this->argument('wallet'));
+
+        if (!$wallet) {
+            return 1;
+        }
+
+        $lastsUntil = $wallet->balanceLastsUntil();
+
+        $this->info("Lasts until: {$lastsUntil}");
+    }
+}
diff --git a/src/app/Entitlement.php b/src/app/Entitlement.php
--- a/src/app/Entitlement.php
+++ b/src/app/Entitlement.php
@@ -52,6 +52,26 @@
         'cost' => 'integer',
     ];
 
+    /**
+     * Return the costs per day for this entitlement.
+     *
+     * @return float
+     */
+    public function costsPerDay()
+    {
+        if ($this->cost == 0) {
+            return (float) 0;
+        }
+
+        $discount = $this->wallet->getDiscountRate();
+
+        $daysInLastMonth = \App\Utils::daysInLastMonth();
+
+        $costsPerDay = (float) ($this->cost * $discount) / $daysInLastMonth;
+
+        return $costsPerDay;
+    }
+
     /**
      * Create a transaction record for this entitlement.
      *
diff --git a/src/app/Utils.php b/src/app/Utils.php
--- a/src/app/Utils.php
+++ b/src/app/Utils.php
@@ -24,7 +24,7 @@
         $start = new Carbon('first day of last month');
         $end = new Carbon('last day of last month');
 
-        return $start->diffInDays($end);
+        return $start->diffInDays($end) + 1;
     }
 
     /**
diff --git a/src/app/Wallet.php b/src/app/Wallet.php
--- a/src/app/Wallet.php
+++ b/src/app/Wallet.php
@@ -116,6 +116,30 @@
         return $charges;
     }
 
+    /**
+     * Calculate for how long the current balance will last.
+     *
+     * @return \Carbon\Carbon Date
+     */
+    public function balanceLastsUntil()
+    {
+        $balance = $this->balance;
+
+        // retrieve any expected charges
+        $expectedCharge = $this->expectedCharges();
+
+        // get the costs per day for all entitlements billed against this wallet
+        $costsPerDay = $this->costsPerDay();
+
+        // the number of days this balance, minus the expected charges, would last
+        $daysDelta = ($balance - $expectedCharge) / $costsPerDay;
+
+        // calculate from the last entitlement billed
+        $entitlement = $this->entitlements()->orderBy('updated_at', 'desc')->first();
+
+        return $entitlement->updated_at->copy()->addDays($daysDelta);
+    }
+
     /**
      * A helper to display human-readable amount of money using
      * the wallet currency and specified locale.
@@ -155,6 +179,22 @@
         );
     }
 
+    /**
+     * Retrieve the costs per day of everything charged to this wallet.
+     *
+     * @return float
+     */
+    public function costsPerDay()
+    {
+        $costs = (float) 0;
+
+        foreach ($this->entitlements as $entitlement) {
+            $costs += $entitlement->costsPerDay();
+        }
+
+        return $costs;
+    }
+
     /**
      * Add an amount of pecunia to this wallet's balance.
      *
diff --git a/src/tests/Feature/EntitlementTest.php b/src/tests/Feature/EntitlementTest.php
--- a/src/tests/Feature/EntitlementTest.php
+++ b/src/tests/Feature/EntitlementTest.php
@@ -32,6 +32,25 @@
         parent::tearDown();
     }
 
+    public function testCostsPerDay(): void
+    {
+        // 444
+        // 28 days: 15.86
+        // 31 days: 14.32
+        $user = $this->getTestUser('entitlement-test@kolabnow.com');
+        $package = Package::where('title', 'kolab')->first();
+        $mailbox = Sku::where('title', 'mailbox')->first();
+
+        $user->assignPackage($package);
+
+        $entitlement = $user->entitlements->where('sku_id', $mailbox->id)->first();
+
+        $costsPerDay = $entitlement->costsPerDay();
+
+        $this->assertTrue($costsPerDay < 15.86);
+        $this->assertTrue($costsPerDay > 14.32);
+    }
+
     /**
      * Tests for User::AddEntitlement()
      */
diff --git a/src/tests/Feature/WalletTest.php b/src/tests/Feature/WalletTest.php
--- a/src/tests/Feature/WalletTest.php
+++ b/src/tests/Feature/WalletTest.php
@@ -2,7 +2,9 @@
 
 namespace Tests\Feature;
 
+use App\Package;
 use App\User;
+use App\Sku;
 use App\Wallet;
 use Tests\TestCase;
 use Illuminate\Foundation\Testing\WithFaker;
@@ -20,6 +22,7 @@
         'WalletControllerB@WalletController.com',
         'WalletController2A@WalletController.com',
         'WalletController2B@WalletController.com',
+        'jane@kolabnow.com'
     ];
 
     public function setUp(): void
@@ -40,6 +43,44 @@
         parent::tearDown();
     }
 
+    public function testBalanceLastsUntil(): void
+    {
+        $user = $this->getTestUser('jane@kolabnow.com');
+        $package = Package::where('title', 'kolab')->first();
+        $mailbox = Sku::where('title', 'mailbox')->first();
+
+        $user->assignPackage($package);
+
+        $wallet = $user->wallets()->first();
+
+        $until = $wallet->balanceLastsUntil();
+
+        // TODO: Test this for typical cases
+        // TODO: Test this for a user with no entitlements
+        // TODO: Test this for a user with 100% discount
+        $this->markTestIncomplete();
+    }
+
+    public function testCostsPerDay(): void
+    {
+        // 999
+        // 28 days: 35.68
+        // 31 days: 32.22
+        $user = $this->getTestUser('jane@kolabnow.com');
+
+        $package = Package::where('title', 'kolab')->first();
+        $mailbox = Sku::where('title', 'mailbox')->first();
+
+        $user->assignPackage($package);
+
+        $wallet = $user->wallets()->first();
+
+        $costsPerDay = $wallet->costsPerDay();
+
+        $this->assertTrue($costsPerDay < 35.68);
+        $this->assertTrue($costsPerDay > 32.22);
+    }
+
     /**
      * Verify a wallet is created, when a user is created.
      */