This online ruler allows you to measure real-world objects directly on your screen. Unlike many ruler online tools, this ruler is accurately calibrated for specific iPhone models, ensuring precise measurements in centimeters and inches.
What Is an Online Ruler?
An online ruler is a digital measuring tool that works directly in your web browser. It allows you to measure objects without installing an app, using your device’s screen as a real-size ruler.
Because screen sizes and resolutions vary between devices, accuracy depends heavily on proper calibration.
How Accurate Is This Online Ruler?
Many ruler online tools rely on generic screen assumptions, which can result in inaccurate measurements. This online ruler is different.
iPhone models have fixed and well-documented screen dimensions. By calibrating the ruler for each iPhone model, this tool provides more reliable real-size measurements in centimeters and inches.
Online Ruler for iPhone (Calibrated by Model)
Please select your smartphone model from the list below.
How to Use This Ruler Online
- Open this page on your iPhone or Android phone.
- Select your exact device model from the list above.
- Place the object directly on the screen.
- Measure the length in centimeters or inches.
Online Ruler vs Other Ruler Online Tools
| Feature | Zyougi Online Ruler | Typical Online Ruler |
|---|---|---|
| Model-based calibration | Yes | No |
| Real-size accuracy | High | Varies |
| iPhone optimization | Yes | No |
| Android support | Yes (Pixel, Galaxy, Xperia…) | Rarely |
Common Uses for an Online Ruler
- Shipping & parcels: quickly check if an item fits within carrier size limits (e.g. 3 cm rule for marketplace shipping)
- Crafts & sewing: measure fabric, paper, or small components without a tape measure
- DIY & home: check gaps, clearances, or small fittings on the spot
- Shopping: verify product dimensions against a listing before you buy
- School & office: quick measurements when a physical ruler isn't nearby
- Ring sizing: combined with our ring size tool, measure finger diameter accurately
Limitations of This Online Ruler
- PC displays may not provide accurate real-size measurements due to variable monitor sizes and scaling settings.
- For Android, select your specific model from the list above — generic Android rulers may be less accurate.
- Screen zoom must be set to 100% for correct results.
FAQ About Online Rulers
Is this online ruler free?
Yes, completely free. No sign-up, no download, no app required — just open the page and start measuring.
Does this online ruler work on Android?
Yes. Select your Android model from the list above (Pixel, Samsung Galaxy, Xperia, AQUOS, and more) for a ruler calibrated to your exact screen size.
Is this ruler online really accurate?
This ruler is calibrated for each specific device model using its documented screen dimensions and pixel density, which makes it significantly more accurate than generic online ruler tools that guess your screen size.
Can I use this online ruler on a PC?
You can open it on a PC, but accurate real-size measurements cannot be guaranteed because PC monitor sizes and scaling settings vary widely.
Do I need to install an app?
No app needed. This online ruler runs entirely in your browser — open the page, select your device, and measure instantly.