Three Ways to Identify a Planner You Already Own
Measure the paper, never the cover
Covers are always bigger than the inserts they hold — often by 10–20mm on each side. Take one page out of the binder, lay it flat, and measure the width and height in millimetres with a ruler. Compare those two numbers against the table above: 148×210mm is A5, 95×171mm is Personal, 105×148mm is true A6, 177.8×233.4mm is Happy Planner Classic. Two numbers are all it takes; do not rely on the word printed on the box, because “A6” and “personal size” are misused constantly in online shops.
Count the rings or discs
Binding hardware is the second fingerprint. Six metal rings in two groups of three almost always mean A5, Personal, Personal Wide, A6 or Pocket — the spacing between groups tells you which. Mushroom-shaped plastic discs mean a disc-bound system: nine discs is Happy Planner Classic, seven is the Mini. Round holes from an office punch will never fit discs, so if you own a disc-bound planner you also need a disc punch before printing inserts at home.
When in doubt, print a test page
Our Print Helper generates a calibration page at any size on this site. Print it at 100% scale, measure the 50mm square with a ruler to confirm your printer is not rescaling, then hold the page against a sheet from your binder. If the outlines and punch marks coincide, you have the right size. This sixty-second test has saved more paper than any other habit — run it before printing a whole month of inserts, and again whenever you change printers, paper trays or binder brands.
量内页，不要量封面
封面永远比内页大一圈——四边常常各宽出 10–20mm。从本子里抽出一页摊平，用尺子量出宽和高的毫米数，再对照上方的尺寸表：148×210mm 是 A5，95×171mm 是 Personal，105×148mm 才是真正的 A6，177.8×233.4mm 是 Happy Planner Classic。只要这两个数字就能确定尺寸；不要轻信包装或商品标题上的字样，因为网店中「A6」「Personal 尺寸」被滥用得非常严重。
数一数活页环或圆盘
装订五金是第二个指纹。六个金属环分成两组、每组三个，基本就是 A5、Personal、Personal Wide、A6 或 Pocket——组间距进一步告诉你是哪一种。蘑菇形塑料圆盘则是圆盘装订系统：九个盘是 Happy Planner Classic，七个盘是 Mini。普通办公打孔器打出的圆孔永远卡不进圆盘，所以圆盘本用户在家打印内页前还需要备一个蘑菇孔打孔器。
拿不准？先打一张测试页
本站的打印助手可以按任意尺寸生成校准页。用 100% 缩放打印出来，拿尺子量一量 50mm 方框确认打印机没有偷偷缩放，再把纸与本子里的内页重叠比对：轮廓和孔位都重合，就说明尺寸选对了。这个一分钟的测试比任何习惯都省纸——打印整月内页之前跑一次，更换打印机、纸盒或本子品牌之后再跑一次。