Measure objects at real size on your screen. Calibrate with your phone model, monitor, or a credit card. Dark theme available.
| Device | PPI | Screen |
|---|---|---|
| iPhone 15 / 16 | 460 | 6.1" OLED |
| iPhone 15 Pro Max | 460 | 6.7" OLED |
| Samsung Galaxy S24 Ultra | 505 | 6.8" AMOLED |
| Samsung Galaxy A55 | 416 | 6.6" AMOLED |
| OnePlus 12 | 446 | 6.82" AMOLED |
| Pixel 8 / 9 | 460 | 6.2" OLED |
| Xiaomi 14 | 446 | 6.36" AMOLED |
| Nothing Phone 2 | 452 | 6.7" OLED |
| MacBook Air M3 | 227 | 13.6" Liquid Retina |
| MacBook Pro 14" | 254 | 14.2" Liquid Retina XDR |
| iPad Pro 12.9" | 264 | 12.9" Liquid Retina XDR |
| Dell 27" 4K Monitor | 163 | 3840 × 2160 |
| Redmi Note 13 Pro | 405 | 6.67" AMOLED |
| Realme 12 Pro+ | 395 | 6.7" AMOLED |
| Vivo V30 | 402 | 6.78" AMOLED |
| Samsung Galaxy A35 | 393 | 6.6" AMOLED |
| iQOO 12 | 388 | 6.78" AMOLED |
| Standard 24" 1080p | 92 | 1920 × 1080 |
| 27" 1440p Monitor | 109 | 2560 × 1440 |
| ThinkPad / HP Laptop | ~110 | 14" 1080p |
After selecting your phone model or calibrating with a credit card, accuracy is within 1-2mm. Browser zoom must be at 100% for best results.
Select your phone model from the device presets. The ruler auto-sets the exact PPI for your device. Supports iPhone, Samsung Galaxy, OnePlus, Pixel, Xiaomi, Nothing Phone, and more.
Yes! Click the moon/sun icon in the top-right corner. Dark theme is great for AMOLED screens (saves battery) and reduces eye strain in low light.
PPI (Pixels Per Inch) measures pixel density. Standard monitors: 96 PPI. Laptops: 110-150 PPI. Phones: 300-500 PPI. The ruler needs your PPI to convert pixels to real-world centimeters or inches.
Yes. Select your phone model for accurate calibration. Hold the phone in landscape mode for a longer ruler. The dark theme works great on AMOLED screens.
Click "Credit Card Calibrate" to show an orange bar. Place a credit card (8.56 cm wide) against your screen. Adjust the PPI slider until the orange bar matches the card width exactly.
No. Dark theme only changes colors. Ruler accuracy depends on PPI calibration, not the theme. Use whichever theme is comfortable for your eyes.