Bar to Atmospheres (bar to atm)

Formula

1 bar = 0.986923 atm

atmospheres = bar × 0.9869232667 — reverse: bar = atmospheres × 1.01325

The factor is derived from the SI definitions of both units (base unit: Pa) 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 bar = 4.93462 atm
• 12.5 bar = 12.3365 atm
• 100 bar = 98.6923 atm

Bar to atmospheres conversion table

FAQ

How many atmospheres are in one bar?

1 bar = 0.986923 atm. 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 bar to atmospheres?

Multiply the value in bar by 0.9869232667: atmospheres = bar × 0.9869232667. For example, 5 bar = 4.93462 atm.

How do I convert atmospheres back to bar?

Multiply by the inverse factor 1.01325 (bar = atmospheres × 1.01325), or use the atmospheres-to-bar page.

Related conversions

• Atmospheres to bar (reverse)
• Pressure Converter — all pressure units in one tool
• Psi to Bar
• Bar to Psi
• Psi to Kilopascals
• Kilopascals to Psi
• Bar to Kilopascals
• Kilopascals to Bar
• Atmospheres to Pascals
• Pascals to Atmospheres

Machine access

• API: GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=bar&to_unit=atm
• MCP: server https://tttkmbb.com/mcp, tool convert_units with {"value":5,"from_unit":"bar","to_unit":"atm"}
• Markdown: https://tttkmbb.com/conversion/bar-to-atm.md · JSON: https://tttkmbb.com/conversion/bar-to-atm.json (add ?value= for a result) · Units: /api/v1/units?quantity=pressure
• 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)