diff --git a/cara/apps/calculator/report_generator.py b/cara/apps/calculator/report_generator.py
index 278a0a79..27abbf80 100644
--- a/cara/apps/calculator/report_generator.py
+++ b/cara/apps/calculator/report_generator.py
@@ -113,6 +113,29 @@ def minutes_to_time(minutes: int) -> str:
 
     return f"{hour_string}:{minute_string}"
 
+def readable_minutes(minutes: int) -> str:
+
+    time = minutes
+    unit = " minute"
+    if time % 60 == 0:
+        time = minutes/60
+        unit = " hour"
+    if time != 1:
+        unit += "s"
+
+    if time.is_integer():
+        time = "{:0.0f}".format(time)
+    else:
+        time = "{0:.2f}".format(time)
+
+    return time + unit
+
+def non_zero_percentage (percentage: int) -> str:
+
+    if percentage < 0.01:
+        return "<0.01%"
+    else:
+        return "{:0.0f}%".format(percentage)
 
 def manufacture_alternative_scenarios(form: FormData) -> typing.Dict[str, models.ExposureModel]:
     scenarios = {}
@@ -223,6 +246,8 @@ def build_report(model: models.ExposureModel, form: FormData):
         loader=jinja2.FileSystemLoader([cara_templates, calculator_templates]),
         undefined=jinja2.StrictUndefined,
     )
+    env.filters['non_zero_percentage'] = non_zero_percentage
+    env.filters['readable_minutes'] = readable_minutes
     env.filters['minutes_to_time'] = minutes_to_time
     env.filters['float_format'] = "{0:.2f}".format
     env.filters['int_format'] = "{:0.0f}".format
diff --git a/cara/apps/calculator/templates/report.html.j2 b/cara/apps/calculator/templates/report.html.j2
index 37fbe14e..2f29d914 100644
--- a/cara/apps/calculator/templates/report.html.j2
+++ b/cara/apps/calculator/templates/report.html.j2
@@ -61,33 +61,8 @@
 			Sliding / Side-Hung</p></li>
 			{% endif %}
 			<li><p class="data_subtext">Opening distance: {{ form.opening_distance }} m</p></li>
-			<li><p class="data_subtext">Windows open: 
-			{% if form.windows_open == "interval" %}
-			{{ form.windows_open }}s of 
-                {% set windows_duration = form.windows_duration %}
-                {% set unit = "minutes" %}
-				{% if windows_duration % 60 == 0 %}
-					{% set windows_duration = form.windows_duration / 60 %} 
-					{% set unit = "hours" %} 
-				{% endif %}
-				{% if windows_duration.is_integer() %}
-					{% set windows_duration = windows_duration | int_format %}
-				{% endif %}
-				{{ windows_duration }} {{ unit }} every
-                {% set windows_frequency = form.windows_frequency %}
-                {% set unit = "minutes" %}
-				{% if windows_frequency % 60 == 0 %}
-					{% set windows_frequency = form.windows_frequency / 60 %} 
-					{% set unit = "hours" %} 
-				{% endif %}
-				{% if windows_frequency.is_integer() %}
-					{% set windows_frequency = windows_frequency | int_format %}
-				{% endif %}
-				{{ windows_frequency }} {{ unit }}
-			{% else %}
-			{{ form.windows_open }}
-			{% endif %}
-			</p></li>
+			<li><p class="data_subtext">Windows open: {{ form.windows_duration | readable_minutes}} 
+				every {{ form.windows_frequency | readable_minutes}}</p></li>
 		</ul>
 			<p class="data_subtext data_italic">When using the natural ventilation option, air flows are calculated using averaged hourly temperatures for the Geneva region, based on historical data for the month selected.</p>
 		{% else %}
@@ -197,7 +172,7 @@
             {% for repeat_event in repeated_events %}
                 <tr>
                     <td>{{ repeat_event.repeats }}</td>
-                    <td>{{ repeat_event.probability_of_infection | int_format }}%</td>
+                    <td>{{ repeat_event.probability_of_infection | non_zero_percentage }}</td>
                     <td style="text-align:right">{{ repeat_event.expected_new_cases | float_format }}</td>
                 </tr>
             {% endfor %}
@@ -220,7 +195,7 @@
             {% for scenario_name, scenario_stats in alternative_scenarios.stats.items() %}
                 <tr>
                     <td>{{ scenario_name }}</td>
-                    <td>{{ scenario_stats.probability_of_infection | int_format }}%</td>
+                    <td>{{ scenario_stats.probability_of_infection | non_zero_percentage }}</td>
                     <td style="text-align:right">{{ scenario_stats.expected_new_cases | float_format }}</td>
                 </tr>
             {% endfor %}