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📏 Length · Weight · Temperature · Area · Volume · Speed · Data
Unit Converter
Convert length, weight, temperature, area, volume, speed, and digital storage units instantly. Covers metric, imperial, and binary data units — results update as you type.
📌 Quick Reference
Length base
Metre (m)
Weight base
Gram (g)
Temperature
°F = (°C × 9/5) + 32
Data base
Byte (B) · binary
How to Use
- 1Select a measurement category using the tab buttons — Length, Weight, Temperature, Area, Volume, Speed, or Data.
- 2Select the unit you are converting from using the left dropdown (From).
- 3Select the unit you want to convert to using the right dropdown (To).
- 4Enter the value in the input field — the result updates instantly as you type.
- 5Use the ⇄ swap button to instantly reverse the conversion direction without re-entering values.
- 6Read the result — very large or very small numbers are shown in scientific notation automatically.
Formula & How It Works
📐 Standard Units (Length, Weight, Volume, Area, Speed, Data)
Method: base-unit conversion 1. Convert input → base unit: base = value × fromFactor 2. Convert base → target unit: result = base ÷ toFactor Example: 100 km → miles base = 100 × 1000 = 100,000 m result = 100,000 ÷ 1609.344 = 62.14 mi
🌡️ Temperature (Offset Formulas)
°C → °F: (°C × 9/5) + 32 °F → °C: (°F − 32) × 5/9 °C → K: °C + 273.15 K → °C: K − 273.15 °F → K: (°F − 32) × 5/9 + 273.15 ⚠ Never use a simple multiplier — the zero-point offset is required.
Common Conversion Reference
| Category | Base Unit | Key Conversions |
|---|---|---|
| Length | Metre (m) | 1 mile = 1.609 km · 1 ft = 0.3048 m · 1 in = 2.54 cm |
| Weight | Gram (g) | 1 kg = 2.205 lb · 1 lb = 453.6 g · 1 tonne = 1,000 kg |
| Temperature | Celsius (°C) | 0 °C = 32 °F = 273.15 K · 100 °C = 212 °F |
| Area | Sq Metre (m²) | 1 acre = 4,047 m² · 1 hectare = 10,000 m² |
| Volume | Litre (L) | 1 US gal = 3.785 L · 1 UK gal = 4.546 L |
| Speed | m/s | 1 km/h = 0.2778 m/s · 1 mph = 0.4470 m/s |
| Data | Byte (B) | 1 KB = 1,024 B · 1 MB = 1,048,576 B (binary) |
Example Calculations
📏 Length: 100 km → miles
Input100 km
To base: 100 × 1,000100,000 m
To miles: ÷ 1,609.34462.137 miles
🌡️ Temperature: 37 °C → °F
Input37 °C (body temp)
× 9/566.6
+ 3298.6 °F
⚖️ Weight: 70 kg → pounds
Input70 kg
To base: 70 × 1,00070,000 g
To lbs: ÷ 453.592154.32 lb
💾 Data: 1 GB → MB
Input1 GB
To base: 1 × 1,073,741,8241,073,741,824 B
To MB: ÷ 1,048,5761,024 MB
Conversion Tips
- 1
Metric vs Imperial — Know When to Use Each
Use metric (SI units) for science, medicine, and international trade. Use imperial for US engineering drawings, American construction specs, and US recipes. Most countries use metric officially; the USA uses both depending on context.
Length: 1 inch = 2.54 cm · 1 foot = 0.3048 m · 1 mile = 1.609 km
- 2
Temperature: Never Use a Simple Multiplier
The most common temperature conversion mistake is multiplying °C by 1.8 without adding 32, which gives the wrong °F result. Always use the full formula with the offset. Kelvin has no negative values — 0 K is absolute zero (−273.15 °C).
°F = (°C × 9/5) + 32 °C = (°F − 32) × 5/9 K = °C + 273.15
- 3
Tonne vs Ton — Verify on Every Invoice
Metric tonne, US short ton, and UK long ton differ by up to 10%. In bulk commodity trading, shipping, and construction materials, using the wrong 'ton' can cause significant pricing errors. Always confirm the unit with your supplier.
Metric tonne = 1,000 kg US short ton ≈ 907 kg UK long ton ≈ 1,016 kg
- 4
US Gallon vs UK Gallon — Not Interchangeable
UK imperial gallon is 20% larger than US gallon. MPG stated in UK figures will always appear higher than the same vehicle's US MPG. When comparing fuel economy across sources, always note the gallon standard used.
US gallon = 3.785 L UK gallon = 4.546 L Difference ≈ +20%
- 5
Digital Storage — Binary vs Decimal
Operating systems use binary (1 KB = 1,024 bytes); hard drive makers use decimal (1 KB = 1,000 bytes). A '1 TB' drive shows as ~931 GiB in Windows because of this difference — not a defect. The IEC introduced Kibibyte (KiB), Mebibyte (MiB) etc. to eliminate this ambiguity.
Binary: 1 GB = 1,073,741,824 bytes (OS) Decimal: 1 GB = 1,000,000,000 bytes (drive spec) Gap: ~7.4% at GB, ~9.1% at TB
- 6
Use the ⇄ Swap Button for Reverse Conversions
Instead of re-selecting both dropdowns for a reverse conversion (e.g. miles to km after km to miles), click the ⇄ swap button. It instantly reverses from and to units while keeping your value — saving time when verifying both directions.
Example: 100 km → 62.14 mi · swap → 100 mi → 160.93 km
Frequently Asked Questions
How does the unit converter calculate results?
Every unit is defined by a fixed conversion factor to a common base unit — metres for length, grams for weight, litres for volume, m/s for speed, and bytes for data. To convert from Unit A to Unit B, the calculator converts your value to the base unit first, then converts to Unit B. Temperature is the exception: Celsius, Fahrenheit, and Kelvin use offset formulas because their zero points differ — not simple multipliers.
Why does temperature conversion use a formula instead of a multiplier?
Water freezes at 0 °C, 32 °F, and 273.15 K — three different numbers for the same physical event. Because the scales have different zero points, conversion requires both multiplication and addition. The correct formulas are: °F = (°C × 9/5) + 32, and K = °C + 273.15. Using a multiplier alone without the offset gives the wrong answer — a common mistake when doing temperature conversions manually.
What is the difference between a metric tonne, a US ton, and a UK ton?
Metric tonne (t) = 1,000 kg. US short ton = 2,000 lb ≈ 907 kg. UK long ton = 2,240 lb ≈ 1,016 kg. This calculator uses the metric tonne. When reviewing commodity invoices, shipping documents, or construction contracts, always confirm which 'ton' is stated — the three differ by up to 10%, which can be significant in bulk pricing.
What is the difference between a US gallon and a UK (imperial) gallon?
A US gallon = 3.785 litres. A UK imperial gallon = 4.546 litres — roughly 20% larger. Fuel economy (MPG) figures stated in US vs UK are therefore not directly comparable. This calculator uses the US gallon for volume conversions. To convert litres to UK gallons, divide by 4.546 (not 3.785).
How are digital storage units (KB, MB, GB, TB) calculated?
This calculator uses binary (IEC) prefixes: 1 KB = 1,024 bytes, 1 MB = 1,048,576 bytes, 1 GB = 1,073,741,824 bytes. This matches how operating systems (Windows, macOS, Linux) report file sizes. Hard drive and SSD manufacturers typically use decimal prefixes (1 GB = 1,000,000,000 bytes), which is why a '1 TB' drive shows slightly less than 1 TB in your file manager.
Is this calculator free and does it store my data?
Yes, completely free with no signup required. All conversions run locally in your browser — no values are sent to any server and nothing is stored or logged. The page works offline once loaded.
References & Standards
- ↗BIPM — International System of Units (SI), 9th Edition
- ↗NIST — US Customary Units and Metric System
- ↗IEC 80000-13 — Binary prefixes (KiB, MiB, GiB)
- ↗IUPAC — Temperature scale definitions
Conversion factors follow international SI definitions and common imperial standards. Temperature formulas use IUPAC-defined thermodynamic scale relationships.