Roman Numeral Converter
Convert any integer to Roman numerals or decode Roman numerals to decimal.
Roman Numeral Converter
Convert any integer to Roman numerals or decode Roman numerals to decimal.
Unit Conversion
ℹ️ All units normalised to a common base before converting to ensure accuracy
Disclaimer
Results provided by this calculator are for informational and educational purposes only. They are based on the values you enter and standard formulas, and should not be considered financial, medical, legal, or professional advice. Always consult a qualified professional before making important decisions based on these results. Roughtools makes no warranties regarding the accuracy or completeness of these calculations for your specific situation.
Frequently Asked Questions
Pro Tips
Always double-check your unit conversion direction — dividing when you should multiply (or vice versa) produces a result off by the conversion factor squared.
For temperature conversions, remember the formulas differ: Celsius to Fahrenheit = (C × 9/5) + 32. Fahrenheit to Celsius = (F − 32) × 5/9. Kelvin = Celsius + 273.15.
Imperial units have multiple definitions (fluid ounce vs weight ounce, US vs UK gallon). Always confirm which system applies — especially for cooking or scientific work.
Significant figures matter in scientific conversions. If your input has 2 significant figures, don't report 6 decimal places of precision — it implies false accuracy.
When to Use This Calculator
Convert between metric and imperial units for temperature, distances, weights, and speeds when travelling abroad.
Convert between US and metric measurements for international recipes or ingredient scaling.
Convert units for scientific calculations where SI units are required.
Convert between measurement systems when working with international suppliers or standards.
Convert units to compare product sizes and prices across different packaging formats.
About the Roman Numeral Converter
This Roman numeral converter translates any integer from 1 to 3,999 into Roman numerals and decodes any Roman numeral back to its decimal value, showing the step-by-step breakdown of the conversion. Enter a number to see the Roman numeral, or type a Roman numeral (e.g. MCMXCIX) to see its decimal value. Includes a reference chart of all Roman numeral symbols and their values. Built for students, designers, clock readers, and anyone working with Roman numerals in film credits, outlines, or legal documents.
How to Use the Roman Numeral Converter
- 1
To convert a number to Roman numerals: enter any integer from 1 to 3,999.
- 2
See the Roman numeral equivalent with a step-by-step breakdown.
- 3
To decode Roman numerals: type the Roman numeral string (e.g. XLII) in the Roman numeral field.
- 4
See the decimal value and a symbol-by-symbol explanation of the decoding.
- 5
Reference the symbol table (I=1, V=5, X=10, L=50, C=100, D=500, M=1000) for manual calculations.
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