A4 Paper Stories

Original Article ↗ Hacker News Discussion ↗

Overall reaction to the article

  • Some readers find the post charming and “peak HN”: everyday math and physical hacks.
  • Others feel it’s long and over-elaborate for what is essentially using paper as a makeshift ruler, something many already do.
  • A few note minor typos/duplicated calculations but otherwise like the exposition on how A0’s dimensions are derived.

Improvised measuring techniques

  • Several alternatives are discussed: carrying string and scissors, marking and reusing midpoints, or using “story sticks” in carpentry to transfer dimensions reliably without re-measuring.
  • Woodworking habits are highlighted: make multiple matching cuts off a single setup, or use an existing piece as the reference instead of re-measuring.
  • Many mention using body parts as approximate standards: thumb–pinky span, fist width, finger segments, arm length.
  • Some rely on phones (physical size or camera/LiDAR measure apps) or pocket tape measures; others humorously recommend IKEA paper tapes.

Properties and use of A‑series (and other ISO) paper

  • Multiple comments explain the √2 aspect ratio: halving or doubling preserves shape, enabling clean scaling between A4, A3, A5, etc.
  • Practical uses: printing two reduced pages per sheet, proofing posters at home, easy document enlargement/shrinking, and efficient industrial cutting from larger sheets.
  • The A0 = 1 m² definition leads directly to a mass trick: with 80 g/m² paper, A4 weighs ~5 g, enabling mental arithmetic for postage or scale calibration.
  • B and C series are mentioned: B as intermediate sizes maintaining the ratio; C sized for envelopes.

Metric vs US paper systems

  • Europeans emphasize the elegance and composability of ISO sizes; Americans note the familiarity and occasional convenience of 8.5×11" (e.g., fitting 80-column text).
  • Pain points with US sizes include inconsistent aspect ratios across formats and needing separate layouts when shrinking posters to letter size.
  • Some note cognitive dissonance when switching regions: letter feels “squat,” A4 “tall.” Availability of A4 in North America is debated.

Units, GSM, and postage

  • There’s a long subthread on “gsm” vs g/m² and general unit notation, with tension between SI purity and industry shorthand.
  • People compare postal thresholds across countries; knowing per-sheet mass lets senders avoid scales where weight limits are tight.