# Pascals to Atmospheres (Pa to atm)

> Convert pascals to atmospheres: 1 Pa = 0.00000986923 atm. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

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

## Formula

- `1 Pa = 0.00000986923 atm`
- `atmospheres = pascals × 0.000009869232667`
- Reverse: `pascals = atmospheres × 101325`

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 Pa = 0.0000493462 atm
- 12.5 Pa = 0.000123365 atm
- 100 Pa = 0.000986923 atm

## Conversion table

| Pascals (Pa) | Atmospheres (atm) |
| --- | --- |
| 1 | 0.00000986923 |
| 2 | 0.0000197385 |
| 3 | 0.0000296077 |
| 4 | 0.0000394769 |
| 5 | 0.0000493462 |
| 6 | 0.0000592154 |
| 7 | 0.0000690846 |
| 8 | 0.0000789539 |
| 9 | 0.0000888231 |
| 10 | 0.0000986923 |
| 15 | 0.000148038 |
| 20 | 0.000197385 |
| 25 | 0.000246731 |
| 30 | 0.000296077 |
| 40 | 0.000394769 |
| 50 | 0.000493462 |
| 75 | 0.000740192 |
| 100 | 0.000986923 |
| 200 | 0.00197385 |
| 250 | 0.00246731 |
| 500 | 0.00493462 |
| 1000 | 0.00986923 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=Pa&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":"Pa","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 pascal?**

1 Pa = 0.00000986923 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 pascals to atmospheres?**

Multiply the value in pascals by 0.000009869232667: atmospheres = pascals × 0.000009869232667. For example, 5 Pa = 0.0000493462 atm.

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

Multiply by the inverse factor 101325 (pascals = atmospheres × 101325), or use the atmospheres-to-pascals page.

## Related conversions

- [Atmospheres to pascals](https://tttkmbb.com/conversion/atm-to-pa.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 Psi](https://tttkmbb.com/conversion/atm-to-psi.md)
- [Psi to Atmospheres](https://tttkmbb.com/conversion/psi-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)