Autoclave Cycle Calculator

Calculate sterilization time, temperature, and pressure for autoclave equipment cycles.

About this calculator

This calculator sets its two clinical numbers -- Temperature and Sterilization Time -- from a single input: Sterilization Type, using the cycle parameters the CDC's Guideline for Disinfection and Sterilization in Healthcare Facilities lays out for steam sterilizers. Gravity Displacement always reports 250°F / 121°C for 30 minutes; Pre-Vacuum always reports 270°F / 132°C for 4 minutes (lines 15-25). Load Type presents four choices -- Unwrapped Instruments, Wrapped Instruments, Porous/Textiles, Mixed Load -- but none of them currently change Temperature, Sterilization Time, or any other result: every branch under a given Sterilization Type sets the identical numbers (lines 16-19 for Gravity, 21-24 for Pre-Vacuum), so switching Load Type alone has no visible effect. The input that actually changes drying is a separate toggle, Wrapped/Pouched Items -- Yes adds 20 minutes of Drying Time, No adds 5 (line 28) -- which is easy to conflate with Load Type's "Wrapped Instruments" option since the two controls sound related but are read independently.

Autoclave Type sets Heat-Up Time (10 minutes tabletop, 15 full-size) and Cool-Down Time (15 minutes tabletop, 25 full-size) (lines 31 and 34). Total Cycle Time is a plain sum of Heat-Up, Sterilization, Drying, and Cool-Down (line 36). Pressure is not its own input at all -- it's derived from the Temperature the Sterilization Type produced: 30 PSI once Temperature reaches 270°F, 15 PSI below that (line 39), so Pressure only ever takes one of two values and moves in lockstep with Sterilization Type.

Inputs

Sterilization Type

Load Type

Wrapped/Pouched Items

Autoclave Type

Tab to move between fields

Results

Total Cycle Time

75 min

Sterilization Time30 min

Temperature250 °F

Temperature121 °C

Pressure15 PSI

Heat-Up Time10 min

Drying Time20 min

Cool-Down Time15 min

Figures current as of 2008. Source: Centers for Disease Control and Prevention, Healthcare Infection Control Practices Advisory Committee (HICPAC). Guideline for Disinfection and Sterilization in Healthcare Facilities (2008): gravity-displacement steam sterilization at 121°C (250°F) for 30 minutes; pre-vacuum steam sterilization at 132°C (270°F) for 4 minutes, for wrapped items.

How to Use This Calculator

Select the sterilization cycle type: Gravity Displacement (121 degrees C) or Pre-Vacuum (132 degrees C).
Choose the load type being sterilized: unwrapped instruments, wrapped instruments, porous/textiles, or a mixed load.
Indicate whether the items are wrapped or pouched, which adds drying time to the cycle.
Select the autoclave type, tabletop/small or full-size, which affects heat-up and cool-down time.
Review the Total Cycle Time along with the sterilization temperature, pressure, and heat-up, drying, and cool-down breakdown.

What each input means

Sterilization Type: Type of autoclave sterilization cycle
Load Type: Informational only — this selection does not currently change the cycle parameters below.
Wrapped/Pouched Items: Whether items are in sterilization pouches
Autoclave Type: Size of the autoclave unit

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Sterilization Type = 1, Load Type = 2, Wrapped/Pouched Items = 1, Autoclave Type = 1 = 4 input(s) provided
Calculate Total Cycle Time
Total Cycle Time
75 = 75
Calculate Sterilization Time
Sterilization Time
30 = 30
Calculate Temperature
Temperature
250 = 250

Figures and sources

Steam sterilization cycle parameters (gravity displacement and pre-vacuum) (2008) — Centers for Disease Control and Prevention, Healthcare Infection Control Practices Advisory Committee (HICPAC). Guideline for Disinfection and Sterilization in Healthcare Facilities (2008): gravity-displacement steam sterilization at 121°C (250°F) for 30 minutes; pre-vacuum steam sterilization at 132°C (270°F) for 4 minutes, for wrapped items.

Engine last updated September 2, 2026. Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.

Frequently Asked Questions

Does changing Load Type (Unwrapped, Wrapped, Porous, Mixed) change my sterilization time or temperature?

No -- currently it doesn't change anything. Temperature and Sterilization Time are set entirely by Sterilization Type (Gravity Displacement or Pre-Vacuum), and every Load Type option under a given Sterilization Type produces identical values (lines 15-25), matching the CDC's published cycle parameters (121°C/250°F for 30 minutes gravity displacement, 132°C/270°F for 4 minutes pre-vacuum) rather than varying by what's loaded. If you're trying to add drying time for pouched items, use the separate Wrapped/Pouched Items toggle instead -- that one does change the result.

What's the difference between the Load Type 'Wrapped Instruments' option and the Wrapped/Pouched Items toggle?

They sound related but are read independently, and only one of them affects the result. Load Type's options, including "Wrapped Instruments", don't change anything in the current calculation (lines 16-19, 21-24). Wrapped/Pouched Items is the control that actually adds Drying Time -- 20 minutes if set to Yes, 5 minutes if set to No (line 28) -- regardless of what Load Type is selected.

Why does Pressure only ever show 15 or 30 PSI?

Pressure isn't a separate input -- it's derived directly from the Temperature that Sterilization Type sets. Once Temperature reaches 270°F, the Pre-Vacuum setting, Pressure reports 30 PSI; below that, at Gravity Displacement's 250°F, it reports 15 PSI (line 39). Since Temperature itself only takes one of those two values, Pressure can never land anywhere in between.

How is Total Cycle Time calculated?

It's a straight sum of four numbers: Heat-Up Time (set by Autoclave Type), Sterilization Time (set by Sterilization Type), Drying Time (set by the Wrapped/Pouched Items toggle), and Cool-Down Time (also set by Autoclave Type) (line 36). Because none of those four pieces vary continuously -- each is one of two fixed values picked by a selection -- Total Cycle Time itself only ever takes one of a handful of fixed combinations.

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