Measurement Guides & Manuals
Step-by-step tutorials and techniques for accurate on-screen measurements.
Flea Market & Shipping Sizing Guide: Thickness Limits & Measurement Techniques
A complete guide to measuring flea market items (Mercari, eBay) and navigating strict 1cm, 2cm, and 3cm shipping thickness limits using an on-screen ruler without plastic gauges.
Unit Conversion Guide: mm, cm, inch, px & On-Screen Ruler Calculations
Complete unit conversion formulas and lookup tables between mm, cm, inches, and px. Covers fractional inch math, display DPI/PPI calculation, and instant on-screen ruler conversion.
What is a Straight Ruler? Differences from Monosashi, Types & Complete Guide
A comprehensive guide to straight rulers (Chokujougi): key differences from traditional monosashi measuring rules, material types (acrylic, steel, aluminum), JIS standards, and proper measurement techniques.
How to Display & Measure with an Actual-Size Ruler on Screen: Complete Guide
A complete guide to displaying a 1:1 real-size ruler in your browser and measuring everyday items accurately on smartphone or PC screens. Covers zoom settings, calibration, and caliper pin controls.
How to Calibrate Your Screen Ruler with a Coin or Card: Complete Guide
Step-by-step instructions on adjusting screen PPI in seconds using standard coins (1-yen, 100-yen) or credit cards for true 1:1 accuracy.
Standard Paper & Card Dimensions Guide: How to Measure with a Screen Ruler
Reference dimensions for business cards, ID cards, A4/B5 sheets, postcards, and photo prints. Learn how to project standard sizes directly onto the screen ruler.
3 Golden Rules for Accurate Screen Measurement
Essential techniques to maintain sub-millimeter precision when measuring with an online ruler in your browser.
Set Browser Zoom to Exactly 100%
If browser zoom is changed to 110% or 125%, physical scale distorts. Press Ctrl/Cmd + 0 to reset to 100% standard zoom.
Perform Real-Object Calibration
Calibrate against a coin (like a 1-Yen coin = 20.0mm) or credit card (85.6mm) to adapt the ruler to your display PPI.
Eliminate Parallax Reading Error
Look perpendicularly (straight down at 90°) to prevent optical distortion caused by the display glass thickness.
Ready to measure on your screen?
Access an accurate, 1:1 real-size screen ruler instantly in your mobile or desktop browser.