Gravity Forms that use a progressbar for multiple pages will adjust as answers are filled in, rather than only when progressing to the next page.

aa-gf-dynamic-progressbar.php

<?php
/*
Plugin Name: A+A Gravity Forms Dynamic Progressbar
Description: Gravity Forms that use a progressbar for multiple pages will adjust as answers are filled in, rather than only when progressing to the next page.
Author: Radley Sustaire, Alchemy + Aim
*/

class AA_GF_Dynamic_Progressbar {
	
	public function __construct() {
		add_filter( 'gform_pre_render', array( $this, 'gform_pre_render' ) );
	}
	
	public function gform_pre_render( $form ) {
		// Run once
		remove_filter( 'gform_pre_render', array( $this, 'gform_pre_render' ) );
		
		if ( !defined('DOING_AJAX') || !DOING_AJAX ) {
			?>
			<script type="text/javascript">
				/** Make the progress bar amount update automatically */
				function aa_auto_progressbar( form_id, $form, $bar ) {
					var debugmode = false;
					var current_progress = -1;
					var $all_fields = $form.find('.gform_body .gfield');

					// Update the progress bar to a percentage.
					// amount = 0.4 will become 40%.
					var set_progress = function( amount ) {
						amount *= 100;

						var percentage = Math.floor(amount) + "%";

						$bar.find('.gf_progressbar_percentage').css('width', percentage );
						$bar.find('span').html( percentage );

						if ( debugmode ) console.log('set_progress: ', percentage);
					};

					// Calculate how many fields are remaining.
					var calculate_progress = function() {
						var filled = 0;
						var total = 0;

						$all_fields.each(function() {
							var $val_inputs = jQuery(this).find('input[type="text"], input[type="email"], textarea, select');
							var $check_inputs = jQuery(this).find('input[type="checkbox"], input[type="radio"]');

							// Ignore text boxes for radio/checkbox fields
							$val_inputs = $val_inputs.filter(function() { return jQuery(this).closest('.gfield_radio, .gfield_checkbox').length === 0; });

							if ( $val_inputs.length > 0 || $check_inputs.length > 0 ) {
								// A field can have multiple inputs, like 5 radio buttons. It's still only one field.
								total += 1;

								// if ANY of those inputs has a value, it should be considered filled.
								if ( $val_inputs.filter(function() { return jQuery(this).val() !== ""; }).length > 0 ) {
									filled += 1; // has value
									if ( debugmode ) console.log('Filled Field:', this);
								} else if ( $check_inputs.filter(function() { return jQuery(this).prop('checked'); }).length > 0 ) {
									filled += 1; // is checked
									if ( debugmode ) console.log('Checked Field:', this);
								}else{
									if ( debugmode ) console.log('Empty field: ', this );
								}
							}
						});

						// Get progress from number of filled fields versus total fields
						var progress = filled / total;

						// Update progress bar if amount changed
						if ( current_progress !== progress ) {
							set_progress( progress );

							// Reset existing classes
							$bar.attr('class', 'gf_progressbar');

							// Interval of 50
							if ( progress >= 0.5 )
								$bar.addClass('over-half');
							else
								$bar.addClass('under-half');

							// Interval of 10
							if      ( progress < 0.05 ) $bar.addClass('perc-0');
							else if ( progress < 0.15 ) $bar.addClass('perc-10');
							else if ( progress < 0.25 ) $bar.addClass('perc-20');
							else if ( progress < 0.35 ) $bar.addClass('perc-30');
							else if ( progress < 0.45 ) $bar.addClass('perc-40');
							else if ( progress < 0.55 ) $bar.addClass('perc-50');
							else if ( progress < 0.65 ) $bar.addClass('perc-60');
							else if ( progress < 0.75 ) $bar.addClass('perc-70');
							else if ( progress < 0.85 ) $bar.addClass('perc-80');
							else if ( progress < 0.95 ) $bar.addClass('perc-90');
							else                        $bar.addClass('perc-100');
						}

						if ( debugmode ) console.log('filled:', filled, '; total:', total, '; progress:', progress);
					};

					// Calculate every time a field changes
					$form.on('change', ':input, textarea, select', calculate_progress);

					// Also calculate immediately
					calculate_progress();
				}
				
				jQuery(function() {
					// Locate the gravity form, the wrapper uses the ID.
					var $wrapper = jQuery('.gform_wrapper' );
					
					if ( $wrapper.length > 0 ) $wrapper.each(function() {
						var form_id = $wrapper.attr('id').replace('gform_wrapper_', '');
						var $form = $wrapper.find( '#gform_' + form_id );
						var $bar = $form.find('.gf_progressbar');
						
						if ( $bar.length > 0 ) {
							aa_auto_progressbar( form_id, $form, $bar );
						}
					});
				});
			</script>
			<?php
		}
		
		return $form;
	}
	
}

new AA_GF_Dynamic_Progressbar();