Temperature conversion (°F ↔ °C)

Convert between Fahrenheit and Celsius for fever assessment and product storage requirements.

What is this for?

Temperature conversion matters in two settings: assessing a reported fever, and verifying that a product has been stored within its labelled range. USP storage definitions are written in Celsius, while US refrigerator and freezer thermometers are frequently in Fahrenheit — so cold-chain verification usually requires a conversion.

How to use it

Select the direction of conversion.
Enter the temperature. Decimals are accepted — clinical thermometers commonly report to one decimal place.
Compare the Celsius result against the fever band, or against the USP storage ranges listed in the result panel.

Worked example

A patient reports a home temperature of 101.3 °F. Convert to Celsius and classify.

Answer: (101.3 − 32) ÷ 1.8 = 38.5 °C — febrile by the ≥38.0 °C definition.

Clinical pearls & pitfalls

The two scales cross at −40°, which is a useful sanity check: if your answer is on the wrong side of −40 relative to the input, you have inverted the formula.
37 °C = 98.6 °F is a historical average, not a threshold. Normal body temperature varies by roughly 0.5 °C over the day and is lower in older adults, so a "normal" reading does not exclude infection in an elderly patient.
USP defines controlled room temperature as 20–25 °C with permitted excursions to 15–30 °C. A pharmacy at 78 °F (25.6 °C) is within the excursion allowance but outside the target range.

Assumptions & limitations

A pure unit conversion. It does not adjust for the measurement site — oral, tympanic, axillary, and rectal readings differ systematically by up to 0.5 °C.
The fever band shown reflects the common ≥38.0 °C definition. Neutropenic fever is defined differently (a single oral reading ≥38.3 °C, or ≥38.0 °C sustained over one hour).

References

United States Pharmacopeia. General Notices and Requirements, 10.30 Storage Temperature.
Freifeld AG, et al. Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the IDSA. Clin Infect Dis. 2011;52(4):e56-e93.
O'Grady NP, et al. Guidelines for evaluation of new fever in critically ill adult patients: 2008 update. Crit Care Med. 2008;36(4):1330-1349.