# Psi to Atmospheres (psi to atm)

> Convert psi to atmospheres: 1 psi = 0.068046 atm. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `psi-to-atm` · Quantity: Pressure (`pressure`, base unit Pa) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/psi-to-atm · This document: https://tttkmbb.com/conversion/psi-to-atm.md · JSON: https://tttkmbb.com/conversion/psi-to-atm.json (add `?value=` for a result)

## Formula

- `1 psi = 0.068046 atm`
- `atmospheres = psi × 0.06804596391`
- Reverse: `psi = atmospheres × 14.69594878`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 5 psi = 0.34023 atm
- 12.5 psi = 0.850575 atm
- 100 psi = 6.8046 atm

## Conversion table

| Psi (psi) | Atmospheres (atm) |
| --- | --- |
| 1 | 0.068046 |
| 2 | 0.136092 |
| 3 | 0.204138 |
| 4 | 0.272184 |
| 5 | 0.34023 |
| 6 | 0.408276 |
| 7 | 0.476322 |
| 8 | 0.544368 |
| 9 | 0.612414 |
| 10 | 0.68046 |
| 15 | 1.02069 |
| 20 | 1.36092 |
| 25 | 1.70115 |
| 30 | 2.04138 |
| 40 | 2.72184 |
| 50 | 3.4023 |
| 75 | 5.10345 |
| 100 | 6.8046 |
| 200 | 13.6092 |
| 250 | 17.0115 |
| 500 | 34.023 |
| 1000 | 68.046 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=psi&to_unit=atm` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":5,"from_unit":"psi","to_unit":"atm"}`
- All pressure units: https://tttkmbb.com/api/v1/units?quantity=pressure · full converter: [Pressure Converter](https://tttkmbb.com/conversion/pressure.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many atmospheres are in one psi?**

1 psi = 0.068046 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 psi to atmospheres?**

Multiply the value in psi by 0.06804596391: atmospheres = psi × 0.06804596391. For example, 5 psi = 0.34023 atm.

**How do I convert atmospheres back to psi?**

Multiply by the inverse factor 14.69594878 (psi = atmospheres × 14.69594878), or use the atmospheres-to-psi page.

## Related conversions

- [Atmospheres to psi](https://tttkmbb.com/conversion/atm-to-psi.md) (reverse)
- [Psi to Bar](https://tttkmbb.com/conversion/psi-to-bar.md)
- [Bar to Psi](https://tttkmbb.com/conversion/bar-to-psi.md)
- [Psi to Kilopascals](https://tttkmbb.com/conversion/psi-to-kpa.md)
- [Kilopascals to Psi](https://tttkmbb.com/conversion/kpa-to-psi.md)
- [Bar to Kilopascals](https://tttkmbb.com/conversion/bar-to-kpa.md)
- [Kilopascals to Bar](https://tttkmbb.com/conversion/kpa-to-bar.md)
- [Atmospheres to Pascals](https://tttkmbb.com/conversion/atm-to-pa.md)
- [Pascals to Atmospheres](https://tttkmbb.com/conversion/pa-to-atm.md)

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)