diff --git a/hub/services/static/css/roi-calculator.css b/hub/services/static/css/roi-calculator.css
index c57342e..a4525fb 100644
--- a/hub/services/static/css/roi-calculator.css
+++ b/hub/services/static/css/roi-calculator.css
@@ -426,6 +426,27 @@
     box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.15);
 }
 
+/* Investment amount input enhancements */
+#investment-amount {
+    font-family: 'Courier New', monospace;
+    font-weight: 600;
+    text-align: right;
+    padding-right: 1rem;
+}
+
+#investment-amount:focus {
+    text-align: left;
+    padding-left: 1rem;
+    padding-right: 0.75rem;
+}
+
+#investment-amount::placeholder {
+    font-family: system-ui, -apple-system, sans-serif;
+    font-weight: normal;
+    text-align: left;
+    opacity: 0.6;
+}
+
 .main-config-fields .form-select {
     border-color: #dee2e6;
     font-size: 1.1rem;
diff --git a/hub/services/static/js/roi-calculator/input-utils.js b/hub/services/static/js/roi-calculator/input-utils.js
index 391088a..94df482 100644
--- a/hub/services/static/js/roi-calculator/input-utils.js
+++ b/hub/services/static/js/roi-calculator/input-utils.js
@@ -44,13 +44,56 @@ class InputUtils {
         }
 
         try {
-            // Remove non-numeric characters except commas
-            let value = input.value.replace(/[^\d,]/g, '');
+            // Allow only digits, no immediate formatting during typing
+            let value = input.value.replace(/[^\d]/g, '');
+            
+            // Handle empty input
+            if (!value) {
+                input.setAttribute('data-value', '0');
+                return;
+            }
 
             // Parse the numeric value
-            let numericValue = InputUtils.parseFormattedNumber(value);
+            let numericValue = parseInt(value) || 0;
 
-            // Enforce min/max limits
+            // Update the data attribute with the raw numeric value (no limits during typing)
+            input.setAttribute('data-value', numericValue.toString());
+
+            // Update the input value (keep it clean, no commas during typing)
+            input.value = value;
+
+            // Update the slider if it exists (with limits)
+            const slider = document.getElementById('investment-slider');
+            if (slider) {
+                const minValue = parseInt(slider.min) || 100000;
+                const maxValue = parseInt(slider.max) || 2000000;
+                const sliderValue = Math.max(minValue, Math.min(maxValue, numericValue));
+                slider.value = sliderValue;
+            }
+
+            // Trigger calculations with debouncing
+            if (window.ROICalculatorApp && window.ROICalculatorApp.calculator) {
+                clearTimeout(input._calculationTimeout);
+                input._calculationTimeout = setTimeout(() => {
+                    window.ROICalculatorApp.calculator.updateCalculations();
+                }, 300); // 300ms delay to avoid excessive calculations during typing
+            }
+        } catch (error) {
+            console.error('Error handling investment amount input:', error);
+            // Set a safe default value
+            input.setAttribute('data-value', '500000');
+            input.value = '500000';
+        }
+    }
+
+    static handleInvestmentAmountBlur(input) {
+        if (!input) return;
+
+        try {
+            // Get the numeric value
+            let numericValue = parseInt(input.getAttribute('data-value')) || 500000;
+
+            // Enforce min/max limits on blur
             const minValue = 100000;
             const maxValue = 2000000;
             
@@ -60,30 +103,43 @@ class InputUtils {
                 numericValue = maxValue;
             }
 
-            // Update the data attribute with the raw numeric value
+            // Update the data attribute with the corrected value
             input.setAttribute('data-value', numericValue.toString());
 
-            // Format and display the value with commas
+            // Format and display the value with commas on blur
             input.value = InputUtils.formatNumberWithCommas(numericValue);
 
-            // Update the slider if it exists
+            // Update the slider
             const slider = document.getElementById('investment-slider');
             if (slider) {
                 slider.value = numericValue;
             }
 
-            // Trigger calculations
+            // Trigger immediate calculation on blur
             if (window.ROICalculatorApp && window.ROICalculatorApp.calculator) {
+                clearTimeout(input._calculationTimeout);
                 window.ROICalculatorApp.calculator.updateCalculations();
             }
         } catch (error) {
-            console.error('Error handling investment amount input:', error);
+            console.error('Error handling investment amount blur:', error);
             // Set a safe default value
             input.setAttribute('data-value', '500000');
             input.value = '500,000';
         }
     }
 
+    static handleInvestmentAmountFocus(input) {
+        if (!input) return;
+
+        try {
+            // Remove commas when focusing for easier editing
+            const numericValue = input.getAttribute('data-value') || '500000';
+            input.value = numericValue;
+        } catch (error) {
+            console.error('Error handling investment amount focus:', error);
+        }
+    }
+
     static getCSRFToken() {
         try {
             // Try to get CSRF token from meta tag first
diff --git a/hub/services/templates/calculator/csp_roi_calculator.html b/hub/services/templates/calculator/csp_roi_calculator.html
index ce2c1b8..133ba32 100644
--- a/hub/services/templates/calculator/csp_roi_calculator.html
+++ b/hub/services/templates/calculator/csp_roi_calculator.html
@@ -27,6 +27,8 @@ function updateCalculations() { window.ROICalculatorApp?.updateCalculations(); }
 function exportToPDF() { window.ROICalculatorApp?.exportToPDF(); }
 function exportToCSV() { window.ROICalculatorApp?.exportToCSV(); }
 function handleInvestmentAmountInput(input) { InputUtils.handleInvestmentAmountInput(input); }
+function handleInvestmentAmountFocus(input) { InputUtils.handleInvestmentAmountFocus(input); }
+function handleInvestmentAmountBlur(input) { InputUtils.handleInvestmentAmountBlur(input); }
 function updateInvestmentAmount(value) { window.ROICalculatorApp?.updateInvestmentAmount(value); }
 function updateRevenuePerInstance(value) { window.ROICalculatorApp?.updateRevenuePerInstance(value); }
 function updateServalaShare(value) { window.ROICalculatorApp?.updateServalaShare(value); }
@@ -139,7 +141,9 @@ document.addEventListener('DOMContentLoaded', function() {
                                     <input type="text" class="form-control" id="investment-amount" 
                                            data-value="500000" value="500,000" 
                                            oninput="handleInvestmentAmountInput(this)"
-                                           onchange="updateCalculations()">
+                                           onfocus="handleInvestmentAmountFocus(this)"
+                                           onblur="handleInvestmentAmountBlur(this)"
+                                           placeholder="Enter amount (100,000 - 2,000,000)">
                                 </div>
                                 <input type="range" class="form-range mt-3" id="investment-slider" 
                                        min="100000" max="2000000" step="50000" value="500000"