How these planners are designed and tested

Writing space

This is the measurement that decides whether a planner is usable, and it is the one most templates get wrong. Comfortable adult handwriting needs about 7 mm of line height. The published rulings are narrow at 6.35 mm, college at 7.1 mm and wide at 8.7 mm; the international general-purpose ruling used in the UK, Germany and India is 8 mm.

Planner-insert makers cite 6.4 to 7.2 mm as preferred. Community discussion consistently lands on 6 to 8 mm with 7 mm most named and 5 mm rejected as unwritable.

Our default writing row is 7.5 mm, deliberately above college-ruled. The absolute floor is 6.35 mm and no file ships below it at any size. For reference, Erin Condren, whose vertical layout the industry copies, ships its hourly planner with 6.35 mm half-hour rows, which is exactly the narrow-ruled minimum.

• Default writing row7.5 mm
• Large print8.7 mm
• Absolute floor6.35 mm, build fails below this
• 30-minute slot8.0 mm comfortable, 6.35 mm floor
• 60-minute slot16.0 mm comfortable, 12.7 mm floor
• Day column38.1 mm target, 32 mm floor for a writing column

Printer margins

Every file uses 12.7 mm, half an inch, on all four sides. That is the smallest single value that clears every manufacturer specification we could find, and the range is wider than most people expect.

Note the HP row in particular: the same printer reserves 3.3 mm on one operating system and 12 mm on another.

Ink and line weights

Planner rules are drawn in DeviceGray rather than RGB, at three weights, and the values are chosen so a weekly reprint does not cost a cartridge and so nothing drops out on a cheap inkjet.

The rule we enforce that most templates do not: a stroke may not be simultaneously thin and light. Either alone survives a home printer; both together do not. A stroke thinner than 0.75 pt must carry at least 15% K, and nothing is ever lighter than 12% K. 5% K is the measured dropout threshold and is forbidden outright.

• Structural rules0.75 pt at 20% K (#CCCCCC)
• Grid and writing lines0.5 pt at 15% K (#D9D9D9)
• Half-hour subdivisions0.5 pt at 15% K, dashed
• Absolute stroke floor0.5 pt. 0.25 pt hairlines are forbidden
• Absolute ink floor12% K (#E0E0E0)

Page geometry

Every size is laid out from scratch for its own page box. Nothing is ever scaled between sizes, and the engine has no scale path at all, so it cannot happen by accident.

The reason is arithmetic: Letter to A5 is roughly a 0.65 linear reduction, which takes a 7.5 mm writing line to 4.9 mm, below the floor, and takes 12.7 mm margins down to about 8 mm.

Imposition

Two size pairs tile their parent sheet at exactly 100%, and the numbers are worth stating because the difference between them is real.

Half Letter on Letter is mathematically perfect: 396 plus 396 is 792 points, which is exactly a landscape Letter sheet. Zero slack. A5 on A4 leaves 2.83 points, which is exactly 1.00 mm, because ISO rounds A5 to 148 mm rather than the 148.5 mm that halving A4 would give. Each child page is centred in its half so the error becomes half a millimetre per side.

We never use the printer driver N-up option and neither should you: it scales a full-size page into a slot, which for Letter into half-Letter is 64.71% and leaves a 35.11 mm white band.

What runs on every build

These are assertions rather than guidelines. A build that would produce a file failing any of them stops.

• Font embeddingevery shipped .ttf is checked for fsType 0, meaning installable embedding with no restriction
• Tabular figuresdigits 0 to 9 asserted to have identical advance widths, so date columns and hour rails cannot rag
• Glyph coverageevery character the engine can draw is asserted present in every font
• Page geometryevery PDF MediaBox checked against its declared size, read from the object graph
• Embedded fontsevery PDF asserted to contain an embedded font file, so nothing falls back to base-14 substitution
• Vector onlyevery PDF asserted to contain zero raster image streams
• Print settingsPrintScaling asserted to be None and the duplex flip edge correct for the sheet
• Hyperlinksdigital editions asserted to contain a non-zero count of link annotations
• Ink safetyno stroke under 0.5 pt, none lighter than 12% K, and none both thin and light
• Week-start coherencethe mini-month first column asserted to match the week grid first column
• Meta uniquenessevery page asserted to have exactly one H1 and a unique title and description

What we have not verified

Stated plainly, because a methodology page that only lists successes is marketing.

The printer margins above are manufacturer specifications rather than our own measurements on those machines. Where a specification differs by operating system we have used the worse figure.

Link behaviour in tablet note-taking apps is compiled from published support documentation and reported user experience; we have tested on a subset of apps and devices, not all of them. Where a claim rests on a source we could not read directly, the guides say so.