Why Millimeter Scale Requires Calibration
When measuring in millimeters, a 5% error on an uncalibrated screen means a difference of 0.5 mm to 1.5 mm—enough to mismatch a machine screw (such as M2 vs. M2.5 vs. M3) or an electronic connector pitch.
By calibrating with a physical card standard (ISO 7810: 85.60 mm), our engine anchors the exact number of CSS pixels per millimeter (cssPxPerMm) directly to your physical display.
Using Guides & Crosshairs for Sub-Millimeter Inspection
Interactive Guide Lines
Click on the millimeter scale at the exact boundary of your component to drop a blue guide line. The floating badge provides a live readout in tenths of a millimeter (e.g. 14.2 mm).
Dual-Axis Crosshair
Enable the crosshair tool to track simultaneous X and Y millimeter coordinates. Ideal for measuring circular coin diameters or rectangular parts.
Standard Metric Screw & Fastener Reference Guide
| Screw Size | Major Thread Diameter | Typical Applications |
|---|---|---|
| M2 | 2.0 mm | Laptops, M.2 SSD drives, glasses |
| M2.5 | 2.5 mm | Electronics enclosures, 3D printers |
| M3 | 3.0 mm | PC computer cases, fans, hobby models |
| M4 | 4.0 mm | Monitor VESA mounts (small), appliances |
| M6 | 6.0 mm | Furniture assembly, bicycles, TV mounts |