diff --git a/templates/invoice-bold/invoice.html b/templates/invoice-bold/invoice.html
index 568fc41e..1685f856 100644
--- a/templates/invoice-bold/invoice.html
+++ b/templates/invoice-bold/invoice.html
@@ -75,7 +75,7 @@
         <th class="col-date">{{ l.date }}</th>
         <th class="col-desc">{{ l.description }}</th>
         <th class="col-qty">{{ l.qty }}</th>
-        <th class="col-unit">{{ l.unit }}</th>
+        <th class="col-unit">{{ unit_header }}</th>
         <th class="col-price">{{ l.unit_price }}</th>
         <th class="col-vat">{{ l.vat }}</th>
         <th class="col-subtotal">{{ l.subtotal }}</th>
diff --git a/templates/invoice-classic/invoice.html b/templates/invoice-classic/invoice.html
index dd73b069..bd6babd7 100644
--- a/templates/invoice-classic/invoice.html
+++ b/templates/invoice-classic/invoice.html
@@ -68,7 +68,7 @@
         <th class="col-date">{{ l.date }}</th>
         <th class="col-desc">{{ l.description }}</th>
         <th class="col-qty">{{ l.qty }}</th>
-        <th class="col-unit">{{ l.unit }}</th>
+        <th class="col-unit">{{ unit_header }}</th>
         <th class="col-price">{{ l.unit_price }}</th>
         <th class="col-vat">{{ l.vat }}</th>
         <th class="col-subtotal">{{ l.subtotal }}</th>
diff --git a/templates/invoice-minimal/invoice.html b/templates/invoice-minimal/invoice.html
index 0d145ee9..9ed0cd7e 100644
--- a/templates/invoice-minimal/invoice.html
+++ b/templates/invoice-minimal/invoice.html
@@ -77,7 +77,7 @@
         <th class="col-date">{{ l.date }}</th>
         <th class="col-desc">{{ l.description }}</th>
         <th class="col-qty">{{ l.qty }}</th>
-        <th class="col-unit">{{ l.unit }}</th>
+        <th class="col-unit">{{ unit_header }}</th>
         <th class="col-price">{{ l.unit_price }}</th>
         <th class="col-vat">{{ l.vat }}</th>
         <th class="col-subtotal">{{ l.subtotal }}</th>
diff --git a/templates/invoice-modern/invoice.html b/templates/invoice-modern/invoice.html
index 07a7a9bd..4afde28d 100644
--- a/templates/invoice-modern/invoice.html
+++ b/templates/invoice-modern/invoice.html
@@ -76,7 +76,7 @@
         <th class="col-date">{{ l.date }}</th>
         <th class="col-desc">{{ l.description }}</th>
         <th class="col-qty">{{ l.qty }}</th>
-        <th class="col-unit">{{ l.unit }}</th>
+        <th class="col-unit">{{ unit_header }}</th>
         <th class="col-price">{{ l.unit_price }}</th>
         <th class="col-vat">{{ l.vat }}</th>
         <th class="col-subtotal">{{ l.subtotal }}</th>
diff --git a/tuttle/rendering.py b/tuttle/rendering.py
index fab9f0b8..b9344c3a 100644
--- a/tuttle/rendering.py
+++ b/tuttle/rendering.py
@@ -227,11 +227,24 @@ def unit_label(raw_unit, quantity=None):
         tpl = labels.get("reminder_n", "{n}. Payment Reminder")
         reminder_title = tpl.format(n=n)
 
+    # Derive the column header from the contract's unit type so that the
+    # rendered invoice makes it explicit whether the quantity column refers
+    # to hours, days, or a fixed price — see issue #358.
+    if getattr(invoice.contract, "is_fixed_price", False):
+        unit_header = labels.get("fixed_price", "fixed price")
+    else:
+        contract_unit = getattr(invoice.contract, "unit", None)
+        if contract_unit is not None:
+            unit_header = unit_label(contract_unit.value, 2)
+        else:
+            unit_header = labels.get("unit", "Unit")
+
     invoice_template = template_env.get_template("invoice.html")
     html = invoice_template.render(
         user=user,
         invoice=invoice,
         l=labels,
+        unit_header=unit_header,
         is_reminder=is_reminder,
         reminder_title=reminder_title,
         notes=invoice.notes,