Discbound planner sizes are a mess, and it is not your fault. Every brand named its own, several of them describe the same piece of paper, and the one thing that would actually tell you whether a page fits — the punch pattern — is almost never printed on the packaging.
So: here is every common size with its real dimensions, which system uses it, and how to print and punch your own inserts rather than buying refills forever.
Every discbound insert size, in one table
| Size | Inches | Millimeters | Used by |
|---|---|---|---|
| A6 | 4.1 x 5.8 | 105 x 148 | Budget binders, pocket inserts |
| Mini | 4.5 x 7 | 114 x 178 | Happy Planner Mini |
| A5 | 5.8 x 8.3 | 148 x 210 | The standard European planner size |
| Half Letter / Junior | 5.5 x 8.5 | 140 x 216 | Arc Junior, TUL Junior, Circa Junior |
| Classic | 7 x 9.25 | 178 x 235 | Happy Planner Classic |
| Letter / Big | 8.5 x 11 | 216 x 279 | Arc, TUL, Circa Letter, Happy Planner Big |
The three that get confused
Half Letter and Junior are the same paper. 5.5 x 8.5 inches, which is a sheet of US Letter cut in half. Arc, TUL and Circa all call it something slightly different. If a listing says one and your planner says the other, they still fit.
A5 is not Half Letter. A5 is narrower and slightly taller: 148 x 210 mm against 140 x 216 mm. Close enough to look identical in a photo, different enough that an A5 page in a Half Letter cover leaves a visible strip along the bottom.
Classic is not Junior. Happy Planner Classic is 7 x 9.25, noticeably wider than a Junior page. This is the swap people make most often, and the extra inch and a half shows.
Page size is only half the answer
The other half is the punch. Discbound pages are not round-hole punched — each hole is a mushroom shape with a narrow neck, which is what lets the page snap on and off the disc without opening anything.
Page size and punch pattern are separate specifications. Two pages can be the same size and still not fit the same discs, and pages of different sizes can share a punch pattern. Happy Planner, Arc and TUL are widely reported as sharing spacing, but the safe move before buying a stack of anything is to hold one page from the pack against your own and check that the necks line up.
We have a whole post on this: are your planner discs compatible?
How to print your own inserts
1. Pick the paper first
Standard 20lb copy paper is too thin for a page that gets snapped on and off discs — the necks tear within a few weeks. Aim for 28lb or heavier, or 32lb if you use fountain pens. Heavier paper also stops the pen showing through, which matters more on a double-sided insert than people expect.
2. Print two-up, then cut
Half Letter is exactly half a sheet of Letter, and A5 is exactly half of A4, so both print two pages to a sheet with no waste. Print two-up, cut down the middle, and you have doubled your yield for the same paper.
Mini and Classic do not divide evenly, so those get printed one to a sheet and trimmed. Annoying, but it is the size that decides this, not your printer.
3. Turn off "fit to page"
This is the single biggest cause of inserts that do not line up. Scale to 100% or "actual size", every time. A page printed at 97% looks fine on its own and is wrong by a couple of millimeters against every other page in the planner — and the error shows up exactly where the punch goes.
Print one test page and measure it with a ruler before printing fifty.
4. Leave room on the punched edge
Keep at least half an inch clear on the side the holes go, and remember that side alternates on a double-sided insert — left on the front, right on the back. If you are designing your own layout, set that margin before anything else, because it is not fixable after you have punched.
5. Punch a few sheets at a time
A discbound punch will physically accept a thick stack and will give you ragged necks if you feed it one. Three or four sheets of 28lb is usually the sweet spot. Tap the stack square against the desk first, and use the guide, not your eye.
No punch? Two ways round it
A discbound punch is the one genuinely expensive part of this, and it is not worth buying to make thirty pages.
- Buy pre-punched filler paper in your size and print onto it. Feed it so the holes end up on the correct edge, and print a single test sheet first — getting the orientation wrong is a rite of passage.
- Punch one master page and trace it. Fine for a handful of sheets, miserable beyond that.
What to print first
Not a year of dated dailies. Almost nobody uses every page of those, and printing twelve months up front is how you end up with a planner you have already fallen behind in.
Start with a month of whatever layout you think you want, plus twenty blank lined or dot grid pages. Use it for four weeks. You will know by the end of it whether you actually want daily pages or just a weekly and somewhere to write, and then you can print the next batch knowing the answer.
Where to go next
If you are still choosing a system, disc-bound vs ring binder vs spiral is the place to start, and converting a ring binder to disc-bound covers the switch. For the discs themselves, planner discs 101 explains size, shape and how many you need.
Discs are in planner discs, and ready-made disc-bound notebooks are in disc-bound notebooks.