In 1 torrs there are 1,000 millitorr. Meanwhile in 1 millitorr there are 0.001 torrs. Keep reading to learn more about each unit of measure and how they are calculated. Or just use the Millitorr to Torrs calculator above to convert any number.
* Values rounded to 6 decimal places for readability
To convert torr to millitorr (mTorr), use the milli- prefix rule. Milli means 1/1,000 of the base unit, so 1 mTorr = 0.001 Torr. That also means 1 Torr = 1,000 mTorr.
Conversion formula (Torr to mTorr):
Quick examples:
Tip: When converting torr to millitorr, you’re moving to a smaller unit, so the number gets bigger by 1,000 times.
1 torr equals 1,000 millitorr.
To convert torr to mTorr, multiply the torr value by 1,000.
Use this formula:
mTorr = torr × 1,000
Example: 0.25 torr × 1,000 = 250 mTorr.
Millitorr means one-thousandth of a torr. The prefix "milli-" equals 0.001. So one torr contains 1,000 millitorr.
In vacuum work, 1 mTorr is often called 1 micron (short for micron of mercury). The values match:
1 micron = 1 mTorr.
Torr and millitorr measure pressure, most often for vacuum levels. You’ll see them in HVAC, lab equipment, coating systems, and vacuum pumps.
They are very close, but not identical by strict definition. In most practical uses, 1 torr is treated as equal to 1 mmHg. For everyday calculations, the difference is usually too small to matter.
Yes. Torr and mTorr can describe absolute pressure when referenced to a perfect vacuum. Many vacuum gauges report pressure in torr or mTorr as absolute values.
Move the decimal three places to the right, then add zeros if needed.
Use the reverse formula:
torr = mTorr ÷ 1,000
Example: 750 mTorr ÷ 1,000 = 0.75 torr.
The Calculate Box tool to convert torrs to millitorr uses the open source script Convert.js to convert units of measurement. To use this tool, simply type a torrs value in the box and have it instantly converted to millitorr.