1 atm = 760 mmHg
1 mmHg = 1/760 atm ≈ 0.001315789 atm
Precision: 6 decimals
Calculator
Current Result
livemmHg: 760
atm: 1
Δ from 1 atm: 0%
History & Example Data
| # | Timestamp | Input | Direction | Output |
|---|
Example Data
Reference pairs commonly used in practice.
| mmHg | atm |
|---|---|
| 0 | 0 |
| 100 | 0.131578947 |
| 250 | 0.328947368 |
| 500 | 0.657894737 |
| 760 | 1 |
| 800 | 1.052631579 |
| -100 | -0.131578947 |
Formula Used
The relationships are based on internationally adopted definitions:
- Standard atmosphere (atm) = 101,325 Pa.
- Millimeter of mercury (mmHg) = 133.322387415 Pa at 0 °C.
Therefore, by ratio: 1 atm = 760 mmHg, and equivalently 1 mmHg = 1/760 atm.
atm = mmHg / 760mmHg = atm × 760This calculator uses exact ratios above, rounding only for display per your chosen decimals.
How to Use This Calculator
- Enter a value in either field: mmHg or atm.
- Pick the direction so the slider follows your intended input.
- Use the slider for quick adjustments in millimeters of mercury.
- Set rounding decimals to control display precision.
- Results update instantly, adding entries to your history on Calculate.
- Export your history or example table as CSV or PDF anytime.
Frequently Asked Questions
Yes. One atmosphere is defined as 760 millimeters of mercury, so conversions use the exact ratio with no approximation, then apply your display rounding preference.
Yes. Negative inputs can represent gauge references or relative pressures below your chosen baseline. The formulas are linear, so negative values convert consistently.
Commonly, four to six decimals are sufficient for engineering. For metrology-grade reporting, pick higher precision and include context on instrument accuracy and environmental conditions.
No. “mm” means millimeter of length, while “mmHg” is millimeters of mercury, a pressure unit. This calculator converts mmHg to atm and vice versa.
The conventional mmHg value references 0 °C for density. For practical conversions, the exact ratio 1 atm = 760 mmHg is standard in most contexts.
Export the example as CSV, edit in a spreadsheet, then reimport elsewhere. Batch input is not built-in here, but history export supports multi‑row reporting.