Free Converters Tools
23 free unit converters — length, weight, temperature, cooking, clothing size, fuel efficiency, data storage, number base and more. Instant. No login.
Whether you need to convert miles to kilometres before a road trip, grams to cups for a recipe, Celsius to Fahrenheit for a weather check, or bytes to gigabytes for a storage calculation — LazyTools has a free converter for it. All 23 converters run instantly in your browser with no sign-up required.
From the free unit converter covering length, weight, temperature, speed, area and volume, to specialist tools like the blood test unit converter, typography unit converter, ring size converter and number to words converter — this collection covers unit conversion for everyday life, cooking, science, engineering and professional work.
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Free Online Unit Converters: The Complete Guide
Unit conversion is one of the most common everyday calculation tasks — and one of the most error-prone when done manually. LazyTools offers 23 free, browser-based converters covering physical quantities, sizes, speeds, electrical units, medical measurements, typography and more. All tools are instant, private and require no account.
Free Temperature Converter — Celsius, Fahrenheit and Kelvin
The free Temperature Converter handles bidirectional conversion between Celsius, Fahrenheit, Kelvin and Rankine. The formula for Celsius to Fahrenheit (F = C x 9/5 + 32) is well-known but easy to mis-apply under pressure — particularly at body temperature (37C = 98.6F), boiling point (100C = 212F) and comfortable room temperature (20C = 68F). The converter displays the formula used alongside the result, making it useful for both quick lookups and students learning unit conversion methodology. Kelvin is essential for scientific applications as the SI base unit of thermodynamic temperature starting at absolute zero (-273.15C).
Free Cooking Unit Converter — Cups, Grams, ml and Tablespoons
The free Cooking Unit Converter solves one of the most frequently-searched conversion problems: US recipe volumes (cups, tablespoons, teaspoons, fluid ounces) to metric weights (grams, millilitres) for common cooking ingredients. The critical insight is that volume-to-weight conversion is ingredient-specific: one cup of all-purpose flour is approximately 120-125g, while one cup of granulated sugar is approximately 200g, and one cup of honey is approximately 340g. The converter maintains density values for common ingredients including various flours, sugars, butter, oils, milk, cream, chocolate and nuts — making it ingredient-aware rather than using a generic water density approximation. Common searches answered: "how many grams is one cup of flour", "convert tablespoons to ml", "2 cups in grams".
Free Data Storage Converter — Bytes, KB, MB, GB, TB
The free Data Storage Converter handles all binary and decimal storage unit conversions: bits, bytes, KB, MB, GB, TB, PB and EB. A frequent source of confusion is the binary vs decimal distinction: hard drive manufacturers use decimal prefixes (1 GB = 1,000,000,000 bytes) while operating systems historically reported storage in binary prefixes (1 GiB = 2 to the power 30 = 1,073,741,824 bytes). This is why a "1TB" drive appears as approximately 931GB in Windows Explorer. The converter supports both conventions with clear labelling.
Free Clothing and Shoe Size Converter
The free Clothing Size Converter maps sizes across UK, US, EU and Australian standards for men's, women's and children's clothing. The Shoe Size Converter does the same for footwear. International online shopping has made these converters indispensable: a UK size 10 men's shoe is a US 10.5 but an EU 44, and these relationships are non-linear — they shift at different points across the size range. The converters account for these irregularities using actual size chart data, not arithmetic approximations. The Ring Size Converter covers UK letter sizing, US/Canadian numeric, European numeric, Japanese sizing and diameter in millimetres.
Free Number Base Converter — Binary, Octal, Decimal and Hex
The free Number Base Converter converts integers between binary (base 2), octal (base 8), decimal (base 10) and hexadecimal (base 16), showing step-by-step working for each conversion direction. Useful for computer science students learning positional number systems, developers converting memory addresses from hex to decimal for debugging, converting colour codes (e.g. #FF5733) to RGB decimal, and understanding bitfield values in embedded systems. The Number to Words Converter converts any number to written English words up to trillions, including ordinal form.
Free Fuel Efficiency, Speed and Energy Converters
The free Fuel Efficiency Converter converts between MPG (US and UK), L/100km and km/L — the relationship is inversely proportional and non-intuitive: 30 MPG equals approximately 7.84 L/100km. The Speed and Distance Converter handles mph, kph, m/s, knots and Mach number, including a distance-time-speed triangle solver. The Energy and Power Converter covers joules, kWh, calories, BTU, watts and horsepower — the full range of units encountered in engineering, physics and energy billing contexts.
Free Medical Blood Test Unit Converter
The free Blood Test Unit Converter converts results between mg/dL (used in the US) and mmol/L (used in the UK, Europe, Canada and Australia) for the most common blood markers: glucose, total cholesterol, LDL, HDL, triglycerides, HbA1c, creatinine, urea and uric acid. Standard normal ranges are displayed in both unit systems alongside the converted value — essential for patients consulting healthcare providers across different countries, and for expatriates comparing results from home-country tests with local reference ranges.
Free Typography Unit Converter for Designers
The free Typography Unit Converter converts between px, pt, em, rem, pica and centimetres with a configurable base font size (default 16px for web, 12pt for print). Particularly useful for front-end developers converting Figma design specifications (which use px) into CSS rem values for scalable, accessible layouts. The Electrical Unit Converter covers volts, amps, watts, ohms, farads and other electrical units. The Pressure Converter handles Pa, kPa, bar, psi, atm and mmHg. The Angle Converter converts degrees, radians and gradians for maths and engineering applications.