A5 is 148 × 210 mm. Half Letter is 5.5 × 8.5 inches, or 139.7 × 215.9 mm. Half Letter is 8.3 mm narrower and 5.9 mm taller.
Which size fits your planner?
Measure an existing page’s width and height, without including the cover or rings. Two pages can look similar while placing the trim edge and punch area in different positions. Match those measurements before selecting a PDF.
| Format | Width | Height |
|---|---|---|
| A5 | 148 mm | 210 mm |
| Half Letter | 139.7 mm | 215.9 mm |
Can you shrink A5 to Half Letter?
Yes, but a proportional resize cannot make both edges match. To fit A5 within Half Letter without cropping, use the smaller ratio: 139.7 ÷ 148 = 0.943919. That gives a scale of about 94.39% and a result measuring 139.7 × 198.22 mm.
The result leaves about 17.68 mm of unused height, or 8.84 mm at each end if centered. These figures assume no additional printable margins. Add margins in the calculator if you print directly on the smaller sheet.
What about Half Letter to A5?
The height limits the opposite conversion: 210 ÷ 215.9 gives about 97.27%. The resulting page is 135.88 × 210 mm, leaving 12.12 mm of total horizontal space. Enlarging it to fill the width would instead make it too tall.
This is why “fill the page” and “fit the page” produce different outcomes. A fill can crop; a fit can leave unused space. Neither operation moves individual text boxes to redesign the layout.
Check the punch area separately
A mathematical fit only compares rectangles. It does not know where your binder holes are. Place a test print behind an existing punched insert and check the text, writing boxes and trim boundary. If a punch overlaps useful content, choose a native-size insert or edit the layout rather than relying on another global resize.
Resizing cannot relocate binder holes
Suppose a guide mark sits 10 mm from the original left edge. At 94.39%, it sits approximately 9.44 mm from the resized edge. If the new page is then centered on a larger sheet, the page offset adds to its position on that sheet. This is why matching the page outline does not guarantee that the holes match your binder.
For two inserts on one sheet, check the two-up layout guide before arranging the pages. A full-sheet outline is not the same thing as an insert’s finished trim boundary.
Check a planner insert before choosing a format
Planner labels are not enough to establish a fit. Even where the page dimensions match, ring spacing, hole diameter and the distance from the punched edge can differ. Compare an existing insert or the manufacturer’s exact template for your model rather than assuming all A5 binders share one punch pattern.
- Measure a loose page from edge to edge; exclude the cover and tabs.
- Measure from the binding edge to the hole centers and check the spacing between centers.
- Mark the writing area and any trim or punch-safe margin.
- Print one candidate insert and place it behind the existing page before punching.
Global scaling changes the hole spacing as well as the text. For instance, a hypothetical 20 mm spacing becomes about 18.88 mm at 94.39%; that example is arithmetic, not a specification for any planner brand. Use a native-size layout when the punch pattern must remain fixed.
Paper dimensions reference: Adobe’s A-series size table. Inch-to-millimeter conversions and worked examples are calculated for this guide.