diff --git a/app.php b/app.php
index aa69fef..ddeef90 100644
--- a/app.php
+++ b/app.php
@@ -17,9 +17,9 @@ class Container
     static SokoWeb\Interfaces\Database\IConnection $dbConnection;
     static SokoWeb\Interfaces\Database\IAuditLogger $auditLogger;
     static SokoWeb\Interfaces\PersistentData\IPersistentDataManager $persistentDataManager;
-    static SokoWeb\Interfaces\Routing\IRouteCollection $routeCollection;
-    static SokoWeb\Interfaces\Session\ISessionHandler $sessionHandler;
-    static SokoWeb\Interfaces\Request\IRequest $request;
+    static ?SokoWeb\Interfaces\Routing\IRouteCollection $routeCollection = null;
+    static ?SokoWeb\Interfaces\Session\ISessionHandler $sessionHandler = null;
+    static ?SokoWeb\Interfaces\Request\IRequest $request = null;
 }
 
 Container::$dbConnection = new SokoWeb\Database\Mysql\Connection($_ENV['DB_HOST'], $_ENV['DB_USER'], $_ENV['DB_PASSWORD'], $_ENV['DB_NAME']);
diff --git a/database/migrations/data/20230428_1826_community_main_currency.php b/database/migrations/data/20230428_1826_community_main_currency.php
new file mode 100644
index 0000000..ce679da
--- /dev/null
+++ b/database/migrations/data/20230428_1826_community_main_currency.php
@@ -0,0 +1,19 @@
+<?php
+
+use RVR\PersistentData\Model\Community;
+use RVR\PersistentData\Model\Currency;
+use SokoWeb\Database\Query\Select;
+
+$select = new Select(Container::$dbConnection);
+$communities = Container::$persistentDataManager->selectMultipleFromDb($select, Community::class);
+
+foreach ($communities as $community) {
+    $mainCurrency = new Currency();
+    $mainCurrency->setCommunity($community);
+    $mainCurrency->setCode($community->getCurrency());
+    $mainCurrency->setRoundDigits(0);
+    Container::$persistentDataManager->saveToDb($mainCurrency);
+
+    $community->setMainCurrency($mainCurrency);
+    Container::$persistentDataManager->saveToDb($community);
+}
diff --git a/database/migrations/structure/20230428_1826_community_main_currency.sql b/database/migrations/structure/20230428_1826_community_main_currency.sql
new file mode 100644
index 0000000..a4b5044
--- /dev/null
+++ b/database/migrations/structure/20230428_1826_community_main_currency.sql
@@ -0,0 +1,4 @@
+ALTER TABLE `communities`
+ADD `main_currency_id` int(10) unsigned DEFAULT NULL,
+ADD KEY `main_currency_id` (`main_currency_id`),
+ADD CONSTRAINT `communities_main_currency_id` FOREIGN KEY (`main_currency_id`) REFERENCES `currencies` (`id`);
diff --git a/src/Controller/CommunityController.php b/src/Controller/CommunityController.php
index a936674..f14225e 100644
--- a/src/Controller/CommunityController.php
+++ b/src/Controller/CommunityController.php
@@ -48,6 +48,8 @@ class CommunityController implements IAuthenticationRequired
             return null;
         }
 
+        \Container::$persistentDataManager->loadRelationsFromDb($community, false);
+
         return new HtmlContent('communities/community', [
             'community' => $community,
             'members' => $this->getMembers($community),
@@ -73,6 +75,63 @@ class CommunityController implements IAuthenticationRequired
         ]);
     }
 
+    public function saveCommunity(): ?IContent
+    {
+        $name = \Container::$request->post('name');
+        if (strlen($name) === 0) {
+            return new JsonContent([
+                'error' => ['errorText' => 'Please fill all required fields!']
+            ]);
+        }
+
+        $communityId = \Container::$request->query('communityId');
+        if ($communityId){
+            if (!$this->checkPermission($communityId, true, $community, $ownCommunityMember)) {
+                return null;
+            }
+        } else {
+            $mainCurrencyCode = \Container::$request->post('main_currency_code');
+            $mainCurrencyRoundDigits = \Container::$request->post('main_currency_round_digits');
+            if (strlen($mainCurrencyCode) === 0 || strlen($mainCurrencyCode) > 3 || $mainCurrencyRoundDigits < 0 || $mainCurrencyRoundDigits > 9) {
+                return new JsonContent([
+                    'error' => ['errorText' => 'Please fill all required fields!']
+                ]);
+            }
+
+            $community = new Community();
+            $community->setCreatedDate(new DateTime());
+        }
+
+        $community->setName($name);
+        \Container::$persistentDataManager->saveToDb($community);
+
+        if (!$communityId) {
+            /**
+            * @var User $user
+            */
+            $user = \Container::$request->user();
+
+            $communityMember = new CommunityMember();
+            $communityMember->setCommunity($community);
+            $communityMember->setUser($user);
+            $communityMember->setOwner(true);
+            \Container::$persistentDataManager->saveToDb($communityMember);
+
+            $mainCurrency = new Currency();
+            $mainCurrency->setCommunity($community);
+            $mainCurrency->setCode($mainCurrencyCode);
+            $mainCurrency->setRoundDigits($mainCurrencyRoundDigits);
+            \Container::$persistentDataManager->saveToDb($mainCurrency);
+
+            $community->setMainCurrency($mainCurrency);
+            \Container::$persistentDataManager->saveToDb($community);
+        }
+
+        return new JsonContent([
+            'redirect' => ['target' => \Container::$routeCollection->getRoute('community')->generateLink(['communityId' => $community->getId()])]
+        ]);
+    }
+
     public function getMembersEdit(): ?IContent
     {
         if (!$this->checkPermission(\Container::$request->query('communityId'), true, $community, $ownCommunityMember)) {
@@ -185,6 +244,10 @@ class CommunityController implements IAuthenticationRequired
         }
 
         $currency = $this->currencyRepository->getById(\Container::$request->query('currency_id'));
+        if ($currency->getId() === $community->getMainCurrencyId()) {
+            return null;
+        }
+
         \Container::$persistentDataManager->deleteFromDb($currency);
 
         return new JsonContent(['success' => true]);
@@ -197,7 +260,7 @@ class CommunityController implements IAuthenticationRequired
         }
 
         $currency = $this->currencyRepository->getByCommunityAndCurrencyCode($community, \Container::$request->query('code'));
-        if ($currency === null) {
+        if ($currency === null || $currency->getId() === $community->getMainCurrencyId()) {
             return null;
         }
 
@@ -261,51 +324,9 @@ class CommunityController implements IAuthenticationRequired
         return new JsonContent(['success' => true]);
     }
 
-    public function saveCommunity(): ?IContent
-    {
-        $name = \Container::$request->post('name');
-        $currency = \Container::$request->post('currency');
-        if (strlen($name) === 0 || strlen($currency) === 0 || strlen($currency) > 3) {
-            return new JsonContent([
-                'error' => ['errorText' => 'Please fill all required fields!']
-            ]);
-        }
-
-        $communityId = \Container::$request->query('communityId');
-        if ($communityId){
-            if (!$this->checkPermission($communityId, true, $community, $ownCommunityMember)) {
-                return null;
-            }
-        } else {
-            $community = new Community();
-            $community->setCreatedDate(new DateTime());
-        }
-
-        $community->setName($name);
-        $community->setCurrency($currency);
-        \Container::$persistentDataManager->saveToDb($community);
-
-        if (!$communityId) {
-            /**
-            * @var User $user
-            */
-            $user = \Container::$request->user();
-
-            $communityMember = new CommunityMember();
-            $communityMember->setCommunity($community);
-            $communityMember->setUser($user);
-            $communityMember->setOwner(true);
-            \Container::$persistentDataManager->saveToDb($communityMember);
-        }
-
-        return new JsonContent([
-            'redirect' => ['target' => \Container::$routeCollection->getRoute('community')->generateLink(['communityId' => $community->getId()])]
-        ]);
-    }
-
     private function getMembers(Community $community): array
     {
-        $members = iterator_to_array($this->communityMemberRepository->getAllByCommunity($community, true));
+        $members = iterator_to_array($this->communityMemberRepository->getAllByCommunity($community, true, [User::class]));
         usort($members, function($a, $b) {
             return strnatcmp($a->getUser()->getDisplayName(), $b->getUser()->getDisplayName());
         });
@@ -318,6 +339,9 @@ class CommunityController implements IAuthenticationRequired
         usort($currencies, function($a, $b) {
             return strnatcmp($a->getCode(), $b->getCode());
         });
+        usort($currencies, function($a, $b) use ($community) {
+            return (int)($b->getId() === $community->getMainCurrencyId()) - (int)($a->getId() === $community->getMainCurrencyId());
+        });
         return $currencies;
     }
 
diff --git a/src/Controller/HomeController.php b/src/Controller/HomeController.php
index f17ceff..2094852 100644
--- a/src/Controller/HomeController.php
+++ b/src/Controller/HomeController.php
@@ -1,5 +1,6 @@
 <?php namespace RVR\Controller;
 
+use RVR\PersistentData\Model\Community;
 use RVR\PersistentData\Model\User;
 use RVR\Repository\CommunityMemberRepository;
 use SokoWeb\Interfaces\Authentication\IAuthenticationRequired;
@@ -27,7 +28,7 @@ class HomeController implements IAuthenticationRequired
         */
         $user = \Container::$request->user();
 
-        $ownCommunityMembers = $this->communityMemberRepository->getAllByUser($user, true);
+        $ownCommunityMembers = $this->communityMemberRepository->getAllByUser($user, true, [Community::class]);
         $communities = [];
         foreach ($ownCommunityMembers as $ownCommunityMember) {
             $communities[] = $ownCommunityMember->getCommunity();
diff --git a/src/Database/AuditLogger.php b/src/Database/AuditLogger.php
index 2e32009..ee477c0 100644
--- a/src/Database/AuditLogger.php
+++ b/src/Database/AuditLogger.php
@@ -6,6 +6,9 @@ class AuditLogger extends AuditLoggerBase
 {
     protected function getModifierId()
     {
+        if (\Container::$request === null) {
+            return null;
+        }
         $user = \Container::$request->user();
         if ($user === null) {
             return null;
diff --git a/src/PersistentData/Model/Community.php b/src/PersistentData/Model/Community.php
index 43b057f..b5b279f 100644
--- a/src/PersistentData/Model/Community.php
+++ b/src/PersistentData/Model/Community.php
@@ -7,12 +7,18 @@ class Community extends Model
 {
     protected static string $table = 'communities';
 
-    protected static array $fields = ['name', 'currency', 'created'];
+    protected static array $fields = ['name', 'currency', 'main_currency_id', 'created'];
+
+    protected static array $relations = ['main_currency' => Currency::class];
 
     private string $name = '';
 
     private string $currency = '';
 
+    private ?Currency $mainCurrency = null;
+
+    private ?int $mainCurrencyId = null;
+
     private DateTime $created;
 
     public function setName(string $name): void
@@ -25,6 +31,16 @@ class Community extends Model
         $this->currency = $currency;
     }
 
+    public function setMainCurrency(Currency $mainCurrency): void
+    {
+        $this->mainCurrency = $mainCurrency;
+    }
+
+    public function setMainCurrencyId(int $mainCurrencyId): void
+    {
+        $this->mainCurrencyId = $mainCurrencyId;
+    }
+
     public function setCreatedDate(DateTime $created): void
     {
         $this->created = $created;
@@ -45,6 +61,16 @@ class Community extends Model
         return $this->currency;
     }
 
+    public function getMainCurrency(): ?Currency
+    {
+        return $this->mainCurrency;
+    }
+
+    public function getMainCurrencyId(): ?int
+    {
+        return $this->mainCurrencyId;
+    }
+
     public function getCreatedDate(): DateTime
     {
         return $this->created;
diff --git a/src/Repository/CommunityMemberRepository.php b/src/Repository/CommunityMemberRepository.php
index b15b8ff..d0a1e2f 100644
--- a/src/Repository/CommunityMemberRepository.php
+++ b/src/Repository/CommunityMemberRepository.php
@@ -13,20 +13,20 @@ class CommunityMemberRepository
         return \Container::$persistentDataManager->selectFromDbById($id, CommunityMember::class);
     }
 
-    public function getAllByCommunity(Community $community, bool $useRelations = false): Generator
+    public function getAllByCommunity(Community $community, bool $useRelations = false, array $withRelations = []): Generator
     {
         $select = new Select(\Container::$dbConnection);
         $select->where('community_id', '=', $community->getId());
 
-        yield from \Container::$persistentDataManager->selectMultipleFromDb($select, CommunityMember::class, $useRelations);
+        yield from \Container::$persistentDataManager->selectMultipleFromDb($select, CommunityMember::class, $useRelations, $withRelations);
     }
 
-    public function getAllByUser(User $user, bool $useRelations = false): Generator
+    public function getAllByUser(User $user, bool $useRelations = false, array $withRelations = []): Generator
     {
         $select = new Select(\Container::$dbConnection);
         $select->where('user_id', '=', $user->getId());
 
-        yield from \Container::$persistentDataManager->selectMultipleFromDb($select, CommunityMember::class, $useRelations);
+        yield from \Container::$persistentDataManager->selectMultipleFromDb($select, CommunityMember::class, $useRelations, $withRelations);
     }
 
     public function getByCommunityAndUser(Community $community, User $user) : ?CommunityMember
diff --git a/views/communities/community.php b/views/communities/community.php
index c703adc..826b724 100644
--- a/views/communities/community.php
+++ b/views/communities/community.php
@@ -16,14 +16,15 @@
         </div>
         <div>
             <h3 class="marginBottom">Currencies</h3>
-            <p>Main currency: <b><?= $community->getCurrency() ?></b></p>
-            <?php if (count($currencies) > 0): ?>
-                <p>Further currencies: <b>
-                    <?php foreach ($currencies as $currency): ?>
+            <?php foreach ($currencies as $currency): ?>
+                <p>
+                    <?php if ($currency->getId() === $community->getMainCurrencyId()): ?>
+                        <b><?= $currency->getCode() ?></b>
+                    <?php else: ?>
                         <a href="<?= Container::$routeCollection->getRoute('community-currency-exchange-rates')->generateLink(['communityId' => $community->getId(), 'code' => $currency->getCode()]) ?>"><?= $currency->getCode() ?></a>
-                    <?php endforeach; ?>
-                </b></p>
-            <?php endif; ?>
+                    <?php endif; ?>
+                </p>
+            <?php endforeach; ?>
             <?php if ($editPermission): ?>
                 <hr>
                 <p><a href="<?= Container::$routeCollection->getRoute('community-currencies')->generateLink(['communityId' => $community->getId()]) ?>">Edit currencies</a></p>
@@ -40,19 +41,23 @@
             <?php endif; ?>
         </div>
         <div>
+            <?php
+            $mainCurrencyCode = $community->getMainCurrency()->getCode();
+            $mainCurrencyRoundDigits = $community->getMainCurrency()->getRoundDigits();
+            ?>
             <h3 class="marginBottom">Finances</h3>
             <table class="fullWidth">
                 <tr>
                     <td>You owe</td>
-                    <td style="text-align: right; color: red;">0 <?= $community->getCurrency() ?></td>
+                    <td style="text-align: right; color: red;"><?= number_format(0, $mainCurrencyRoundDigits) ?> <?= $mainCurrencyCode ?></td>
                 </tr>
                 <tr>
                     <td>You're owed</td>
-                    <td style="text-align: right; color: green;">0 <?= $community->getCurrency() ?></td>
+                    <td style="text-align: right; color: green;"><?= number_format(0, $mainCurrencyRoundDigits) ?> <?= $mainCurrencyCode ?></td>
                 </tr>
                 <tr>
                     <td>Your balance</td>
-                    <td style="text-align: right;">0 <?= $community->getCurrency() ?></td>
+                    <td style="text-align: right;"><?= number_format(0, $mainCurrencyRoundDigits) ?> <?= $mainCurrencyCode ?></td>
                 </tr>
             </table>
         </div>
diff --git a/views/communities/community_currencies.php b/views/communities/community_currencies.php
index 9f51ec5..27b1d95 100644
--- a/views/communities/community_currencies.php
+++ b/views/communities/community_currencies.php
@@ -21,9 +21,11 @@
                     <td>
                         <input type="number" form="editCurrency_<?= $currency->getId() ?>" class="text fullWidth" name="round_digits" value="<?= $currency->getRoundDigits() ?>" min="0" max="9" required>
                     </td>
-                    <td style="text-align: right;">
-                        <button type="submit" form="editCurrency_<?= $currency->getId() ?>" name="submit" class="small marginRight" disabled>Save</button><!--
-                     --><button type="submit" form="deleteCurrency_<?= $currency->getId() ?>" class="small red">Delete</button>
+                    <td style="text-align: right; font-size: 0;">
+                        <button type="submit" form="editCurrency_<?= $currency->getId() ?>" name="submit" class="small" disabled>Save</button>
+                        <?php if ($currency->getId() !== $community->getMainCurrencyId()): ?>
+                            <button type="submit" form="deleteCurrency_<?= $currency->getId() ?>" class="small red marginLeft">Delete</button>
+                        <?php endif; ?>
                     </td>
                 </tr>
             <?php endforeach; ?>
diff --git a/views/communities/community_edit.php b/views/communities/community_edit.php
index bd2b0e1..d7e08f7 100644
--- a/views/communities/community_edit.php
+++ b/views/communities/community_edit.php
@@ -16,7 +16,10 @@
         ?>
         <form id="communityForm" action="<?= $formAction ?>" method="post" data-redirect-on-success="true">
             <input type="text" class="text big fullWidth" name="name" placeholder="Name" value="<?= isset($community) ? $community->getName() : '' ?>" required>
-            <input type="text" class="text big fullWidth marginTop" name="currency" value="<?= isset($community) ? $community->getCurrency() : '' ?>" placeholder="Default currency" maxlength="3" required>
+            <?php if (!isset($community)): ?>
+                <input type="text" class="text big fullWidth marginTop" name="main_currency_code" placeholder="Main currency" maxlength="3" required>
+                <input type="number" class="text big fullWidth marginTop" name="main_currency_round_digits" placeholder="Main currency round digits" min="0" max="9" required>
+            <?php endif; ?>
             <p id="communityFormError" class="formError justify marginTop"></p>
             <div class="right marginTop">
                 <button type="submit" name="submit"><?= isset($community) ? 'Save' : 'Create' ?></button>