How to Build a Sliding Paper Progress Bar Into a Pop-Up Card

The display has three layers: a backing panel, two spacer rails, and a front panel containing a rectangular window. A two-color strip moves between the rails. At the starting position, the window shows the blank half; pulling the strip right brings the colored half into view from the left.

This uses the straight-line motion described in Oak National Academy’s Card slider mechanisms: a slider needs a guide to control its movement and accurate cutting and measuring. Here, the rails provide that guide.

The pop-up and slider operate separately. The card fold raises the display, and your hand sets its progress. This arrangement lets you adjust the reading while the card stands open, without designing a linkage between the fold angle and the bar position.

Gather cardstock for the card and display panels, smooth paper or thin card for the moving strip, paper adhesive or narrow double-sided tape, a ruler, pencil, scissors, a scoring tool, and your preferred tool for cutting the window. Use a contrasting color for the filled portion.

All dimensions below are in millimeters. Width runs left to right; height runs top to bottom when viewing the finished display.

Piece	Dimensions	Purpose
Inner card	200 × 160	Fold across the middle to make two 200 × 80 halves
Optional outer cover	200 × 160	Conceals the cuts behind the pop-up
Display backing	120 × 40	Supports the slider channel
Display front	120 × 40	Contains the progress window
Moving strip	120 × 14	Carries the colored and blank sections
Spacer rails	Two strips, each 120 × 5, with extra copies as needed	Separate the front from the backing
Decorative pop-up label	Optional, sized after testing	Adds a short project title

Make the spacer rails thicker than the moving strip by laminating additional rail layers if needed. The required number depends on your materials and adhesive. Choose the stack through a sliding test: the strip should move without being squeezed between the panels.

Keep the moving strip flat. Gathered’s mechanical slider card tutorial likewise advises keeping sliding panels flat and free of embellishments for smooth movement. Put raised decoration on stationary areas after testing the mechanism.

Place the display front horizontally. Treat its upper-left corner as the measurement origin. Mark a window extending from 60 to 100 mm across the panel and from 16 to 24 mm down. Cut out that 40 × 8 mm rectangle.

Draw a fine outline around the opening. Above it, mark 0%, 25%, 50%, 75%, and 100% at horizontal positions 60, 70, 80, 90, and 100 mm. These marks describe the filled length visible through the window.

On the moving strip, color the entire left-hand 60 × 14 mm area. Leave the right-hand 60 × 14 mm area blank, using a color that differs clearly from the fill. Make the boundary straight and perpendicular to the strip’s long edges. Drawing or printing the color directly avoids adding another paper layer inside the channel.

When the strip’s left end aligns with the panel’s left edge, the color boundary sits at 60 mm, exactly at the window’s left edge. Moving the strip right shifts that boundary across the window.

Place the backing horizontally. Attach one rail between 7 and 12 mm down from its top edge, and the other between 28 and 33 mm down. This leaves a 16 mm-high channel for the 14 mm-high strip, with approximately 1 mm of clearance above and below when centered.

Lay the moving strip in the channel with its colored half on the left. Align its left end with the backing’s left edge. Place the windowed front over the assembly without attaching it yet. Through the window, you should see only the blank section.

Hold the layers together gently and slide the strip 40 mm to the right. The color should now fill the entire window. Check the halfway position too: a 20 mm pull should fill half the opening. If the strip tilts, inspect rail alignment and the strip’s cut edges.

Remove the slider before attaching the front panel. Apply adhesive only to the outward-facing rail surfaces, then align and attach the front to the backing. Leave both ends of the channel open. Allow the adhesive to set before reinserting the strip.

To make the flush strip accessible at zero, cut a shallow semicircular finger notch in the front panel’s right edge, centered on the channel. Keep the notch between the rails. Pinch the exposed strip through this notch to begin the pull.

Fold the 200 × 160 mm inner card across its middle, producing a 200 × 80 mm folded card. With the folded edge facing you, mark positions 40 and 160 mm along that edge. At each position, cut 25 mm inward, perpendicular to the fold. Score between the ends of those two cuts.

Crease the resulting wide flap in both directions, unfold the card, and reverse the flap inward. Open the card to approximately 90 degrees to form the box step. This follows the cut, score, and reverse-fold method in Extreme Cards and Papercrafting’s original simple box pop-up tutorial.

The step is 120 mm wide, matching the display. Identify its upright face—the face that stands approximately parallel to the back half of the open card. Position the display backing against that face, aligning their bottom edges and centering them horizontally. The 40 mm-high display will extend 15 mm above the 25 mm-high support.

Temporarily hold the display in position and close the card slowly with the slider reset to zero. Check that the panel folds inside the card and that its corners clear the surrounding paper. Only then attach the lower portion of the display backing to the upright face. Keep adhesive off the folds and away from the slider openings.

If adding an outer cover, attach it to the flat areas behind the inner card after checking the mechanism. Leave the reverse-folded box area free so it can move inward. The designer’s tutorial also recommends checking that attached decoration remains inside the closed card before gluing.

For this layout, the required pull distance follows directly from the 40 mm window length: pull distance = 40 mm × desired percentage ÷ 100. These are geometric readings for the paper display; you decide what activity or set of craft steps they represent.

Display reading	Pull distance from zero	Colored window length
0%	0 mm	0 mm
25%	10 mm	10 mm
50%	20 mm	20 mm
75%	30 mm	30 mm
100%	40 mm	40 mm

At zero, the strip’s right end is flush with the display’s right edge. At full progress, it projects 40 mm beyond that edge. Measure these positions from the strip itself rather than estimating them from the colored window.

Add a fine vertical line on the strip 80 mm from its left end. Write “STOP” immediately to the right of the line. At full progress, this line reaches the sleeve’s right edge. It is a visual travel limit; this simple sleeve has no mechanical stop, and continuing to pull will remove the strip.

For an illustrative four-stage paper project, each completed stage could correspond to a 10 mm pull. Use stage labels instead of percentages if the stages represent different amounts of work. Reset the slider before closing the card so the projecting tab stays within the folded card.

Test the sleeve on its own first, then test it again on the pop-up. That sequence helps identify whether an issue comes from the sliding channel or the folding support.

What happens	What to inspect	Adjustment
Strip sticks throughout its travel	Rail height, glue intrusion, or bent strip	Open the sleeve and clear the channel; increase spacer thickness if needed
Strip moves diagonally	Rails are not parallel, or the strip is uneven	Realign the rails or recut the strip square
Color shows at zero	Strip is not flush left, or the color boundary is misplaced	Realign the strip; confirm the boundary is 60 mm from its left end
Window is not full after a 40 mm pull	Window length or boundary position differs from the layout	Remeasure both before changing the travel marks
Card resists closing	Display placement, projecting slider, or decoration interferes	Reset the strip, remove decoration, and repeat the temporary placement test

Finish with flat labels near the scale and a short instruction such as “Open, then pull to set progress.” Cycle the card open and closed, check the empty, halfway, and full positions, and confirm that the slider can be reset through the finger notch. Add the final decoration only when those movements work together.

• Card slider mechanisms — Oak National Academy
• How to Make Simple Box Pop Up Cards {Throwback Thursday} — Extreme Cards and Papercrafting
• How to make a mechanical slider card — Gathered