Electronvolts to Joules (eV to J)

Formula

1 eV = 1.60218e-19 J

joules = electronvolts × 1.602176634e-19 — reverse: electronvolts = joules × 6241509074000000000

The factor is derived from the SI definitions of both units (base unit: J) as listed in NIST SP 811; results on this page are shown to 6 significant figures, the API returns up to 12.

Worked examples

• 5 eV = 8.01088e-19 J
• 12.5 eV = 2.00272e-18 J
• 100 eV = 1.60218e-17 J

Electronvolts to joules conversion table

FAQ

How many joules are in one electronvolt?

1 eV = 1.60218e-19 J. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

What is the formula to convert electronvolts to joules?

Multiply the value in electronvolts by 1.602176634e-19: joules = electronvolts × 1.602176634e-19. For example, 5 eV = 8.01088e-19 J.

How do I convert joules back to electronvolts?

Multiply by the inverse factor 6241509074000000000 (electronvolts = joules × 6241509074000000000), or use the joules-to-electronvolts page.

Related conversions

• Joules to electronvolts (reverse)
• Energy Converter — all energy units in one tool
• Kilocalories (food calories) to Kilojoules
• Kilojoules to Kilocalories (food calories)
• Joules to Calories (small, thermochemical)
• Calories (small, thermochemical) to Joules
• Kilowatt-hours to Megajoules
• Megajoules to Kilowatt-hours
• Kilowatt-hours to BTU
• BTU to Kilowatt-hours

Machine access

• API: GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=eV&to_unit=J
• MCP: server https://tttkmbb.com/mcp, tool convert_units with {"value":5,"from_unit":"eV","to_unit":"J"}
• Markdown: https://tttkmbb.com/conversion/ev-to-joules.md · JSON: https://tttkmbb.com/conversion/ev-to-joules.json (add ?value= for a result) · Units: /api/v1/units?quantity=energy
• OpenAPI operationId: convert_units. Freshness: static. Authentication: none.

Sources

• NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors (standard)
• BIPM – The International System of Units (SI Brochure, 9th edition) (standard)
• Wikipedia – Conversion of units (reference)