Unit Converter Methodology
Last updated: February 2025
Overview
Our unit converters use internationally standardized conversion factors defined by the International System of Units (SI), National Institute of Standards and Technology (NIST), and International Organization for Standardization (ISO). These are the same standards used in science, engineering, and international trade.
Key Conversion Standards
Length Conversions
| 1 inch | = 2.54 cm (exact) |
| 1 foot | = 0.3048 m (exact) |
| 1 mile | = 1.609344 km (exact) |
| 1 nautical mile | = 1.852 km (exact) |
Mass/Weight Conversions
| 1 pound (lb) | = 0.45359237 kg (exact) |
| 1 ounce (oz) | = 28.349523125 g |
| 1 stone | = 6.35029318 kg |
Temperature Conversions
°C = (°F - 32) × 5/9°F = (°C × 9/5) + 32K = °C + 273.15Volume Conversions
| 1 US gallon | = 3.785411784 L (exact) |
| 1 UK gallon | = 4.54609 L (exact) |
| 1 fluid ounce (US) | = 29.5735295625 mL |
Digital Storage
| 1 KB (kilobyte) | = 1,000 bytes (SI) |
| 1 KiB (kibibyte) | = 1,024 bytes (binary) |
| 1 GB | = 1,000,000,000 bytes (SI) |
We follow SI prefixes (decimal) per IEC 80000-13 standard.
Official Data Sources
- NIST Special Publication 330 - The International System of Units (SI)
- NIST Handbook 44 - Specifications for commercial weighing and measuring
- ISO 80000 - Quantities and units standard
- Bureau International des Poids et Mesures (BIPM) SI Brochure
Precision & Rounding
Our converters use high-precision floating-point arithmetic and display results with appropriate significant figures. For most practical purposes, displayed precision exceeds measurement accuracy. Scientific and engineering applications may require verification against original sources for critical calculations.
Update Frequency
Unit conversion factors are internationally standardized and rarely change. We review our converters annually to ensure alignment with current SI definitions (last major update: 2019 SI redefinition). Currency converters, where applicable, use real-time exchange rate APIs.