Universal Converter

Universal Unit Converter

Convert between 50+ units across 8 clinical and general categories, weight, height, volume, pressure, temperature, speed, area, and length. Bidirectional and real-time: type in either field and both update instantly.

Real-time bidirectional NIST exact factors No data stored
Common Weight Conversions

About This Unit Converter

This converter uses exact NIST-defined conversion factors for physical units, ensuring accuracy to full floating-point precision. All calculations happen instantly in your browser, no server requests, no latency, and no data transmitted. Conversion factors follow NIST-published standard values.

Why Accuracy Matters in Clinical Conversions

In clinical practice, unit conversion errors have caused serious medication incidents, notably when weight in lbs was misread as kg (a 2.2× error) or when blood pressure was confused between mmHg and kPa. See our Weight-Based Dose Calculator for a purpose-built tool that eliminates this specific risk. Our converter explicitly labels all units and uses exact conversion factors, not rounded approximations.

Categories Covered

  • Weight: kg, g, lbs, stone, oz, mg, mcg, for body weight and drug dosing
  • Height: cm, m, inches, feet+inches, for clinical measurements
  • Volume: mL, L, fl oz, tsp, tbsp, cups, pints, for fluid and medication volumes
  • Pressure: mmHg, kPa, cmH₂O, atm, bar, psi, for blood pressure (a direct input to risk tools like the Framingham Risk Score) and ventilator settings
  • Temperature: °C, °F, K, with clinical reference bands
  • Speed: km/h, mph, m/s, knots
  • Area: cm², m², in², ft²
  • Length: mm, cm, m, km, in, ft, yd, miles

Blood Pressure Units in Practice

Blood pressure is measured in mmHg in most of the world, including the US, UK, and most clinical guidelines; the CDC states a healthy reading as under 120/80 mmHg. kPa appears mainly in some European academic and research contexts, and occasionally on ventilators alongside cmH₂O. If you're reading a value in an unfamiliar unit, converting it before comparing to a standard reference range avoids misinterpreting a normal reading as abnormal or vice versa.

Frequently Asked Questions

How do I convert stone to kg?+
One stone = 6.35029 kg (exactly). So 11 stone = 11 × 6.35029 = 69.85 kg. Many UK patients report weight in stone, use this converter to quickly translate to kg for clinical calculations. Select Weight category, set "From" to Stone and "To" to kg.
What is the difference between mmHg and kPa for blood pressure?+
Both measure pressure. 1 mmHg = 0.133322 kPa. Blood pressure of 120/80 mmHg = 16.0/10.7 kPa. The UK and some European countries commonly report blood pressure in mmHg, but kPa is used in some academic and research contexts, and is the SI unit of pressure. Ventilator pressures are often expressed in cmH₂O (1 cmH₂O = 0.0980665 kPa).
How many mL are in a teaspoon?+
One US teaspoon = 4.92892 mL (often rounded to 5 mL in medication instructions). One UK teaspoon = 5.91939 mL. Most clinical medication instructions use 5 mL as the standard teaspoon. When dispensing liquid medications, always use a calibrated measuring spoon or syringe rather than a household teaspoon, which varies significantly in volume.

Related Converters

For medication dose unit conversion (mcg to mg, mg/kg to total dose), see Medication Dose Converter. For laboratory value conversion (mg/dL to mmol/L), see Lab Values Converter. For temperature specifically with clinical fever thresholds, see Temperature Converter.

⚠️ Note: Always verify critical clinical conversions, particularly drug doses and body weight, with a second source before acting on them in patient care.