Charter Flight Cost Calculator December 28, 2025December 28, 2025 by Marketing ROI Calculator Calculate your return on investment for SEO and Ad campaigns. Total Investment ($) Total Revenue ($) 0 && revenue >= 0) { var roi = ((revenue – spend) / spend) * 100; display.innerHTML = 'Your ROI: ' + roi.toFixed(2) + '%'; display.style.display = 'block'; } else { alert('Please enter valid positive numbers'); }" style="width: 100%; background-color: #0073aa; color: white; padding: 12px; border: none; border-radius: 4px; cursor: pointer; font-size: 16px; font-weight: 600;">Calculate ROI Formula: [(Revenue – Investment) / Investment] x 100