All Tools VerseRoman Numeral Converter
Convert between decimal numbers and Roman numerals in either direction, for values from 1 to 3999.
- Runs in your browser
- Nothing uploaded
- Free, no sign-up
Converted locally in your browser. Your input never leaves this tab.
How to Use Roman Numeral Converter
- Enter a value. A number from 1 to 3999, or a Roman numeral.
- Convert. The tool detects the direction automatically.
- Read the result. A number becomes a numeral, and a numeral becomes a number.
- Copy the result. Click Copy result. It all runs in your browser.
Frequently Asked Questions
Does it convert both ways?
Yes. Enter a number to get its Roman numeral, or enter a numeral to get the number. The direction is detected from what you type.
What range is supported?
Numbers from 1 to 3999, which is the standard range for classic Roman numerals using the letters I to M.
What if I enter an invalid numeral?
The tool checks that the numeral is well formed, so a malformed entry like IIII is reported as invalid rather than converted.
Which letters are used?
I, V, X, L, C, D, and M, combined with the usual subtractive pairs such as IV for four and IX for nine.
Is anything uploaded?
No. The conversion runs in your browser, so your input never leaves the tab.
Related Tools
Convert Hex to Roman Numeral →
Convert hex to Roman numerals with vinculum (overline) support up to 3,999,999. Batch mode,…
Convert Roman Numeral to Hex →
Convert Roman numerals to hex (and back) with strict 1-3999 validation. Batch TSV output.…
Angle Converter - Degrees, Radians, Gradians →
Free angle converter. Switch between degrees, radians, gradians, arcminutes and arcseconds instantly. Runs in…
Area Converter - Square Meters, Feet, Acres →
Free area converter. Switch between square meters, square feet, acres, hectares and square miles…
ASCII Case Converter →
Transform any text into Uppercase, Lowercase, Title Case, or Sentence Case safely formatting paragraphs…
Bionic Reading Converter →
Bionic Reading Converter format instantly. Bold word prefixes for faster reading. Free, offline, client-side,…
Case Converter →
Case Converter use on any text to sentence, UPPER, lower, Title, camel, snake or…
Color Converter →
Color Converter any colour between HEX, RGB, HSL, HSV, and CMYK. Accepts alpha and…
CSS Unit Converter →
Convert between 23 CSS units (px/em/rem/pt/%/ch/vmin/vmax/dvw/cqw…) with property context + comparison table. Free, offline,…
Data Storage Converter - MB, GB, MiB, GiB →
Free data storage converter. Switch between bytes, KB, MB, GB, TB and binary KiB,…
Data Transfer Rate Converter - Mbps to MB/s →
Free data transfer rate converter. Switch between Mbps, MB/s, Gbps and more instantly. Runs…
Energy Converter - Joules, Calories, kWh, BTU →
Free energy converter. Switch between joules, calories, kcal, watt hours, kWh and BTU instantly.…