Use a credit card to calibrate the ruler anywhere, when you don't have a real ruler with you!

- Pick your units: fractional inches, centimeters or millimeters
- Calibrate your ruler with a credit card to get you started anytime, anywhere
- Calibrate your ruler with a real ruler to achieve the best precision in your measurement transfers
- Manually set the ruler to a known length for accurate measurements
- Save your measurements for future use
- No permission required