Everyday Exposure
Every everyday exposure calculator on CalcEngines — each with its formula, a worked example, the standard it follows and the assumptions it makes.
2 calculators in this section
- Caffeine Half-Life Calculator (Several Doses, Named Published Half-Lives)First-order elimination from up to three doses at different times of day, to a bedtime you set, with the half-life as an explicit input rather than a hidden constant — because the half-life is almost the whole answer. The commonly quoted figure of about 5 hours sits inside a measured adult range of 2.3 to 9.9 hours, and on the same three cups those two ends differ by more than the headline itself. Named presets carry the published figures for smoking, oral contraceptives, pregnancy and cirrhosis, each with its source. Published daily intakes are reported with the body that published them and are not framed as a safe amount: the FDA's 400 mg a day for most adults, and ACOG's statement about less than 200 mg a day in pregnancy, which is a finding about miscarriage and preterm birth and not a limit.
- Heat Index Calculator (NOAA/NWS Rothfusz Regression, °C and °F)The heat index in °C and °F from air temperature and either relative humidity or dew point, computed with the full NOAA/NWS Rothfusz regression and both of the documented adjustments that most implementations leave out. Banded on the four published National Weather Service categories, with the India Meteorological Department's experimental °C thresholds shown beside them rather than resolved, because the two schemes disagree by a wide margin. Three things this page will keep saying: the figure assumes shade and NOAA's own statement is that full sunshine can add up to 15 °F; it is not WBGT, which is what sports and occupational bodies use for activity limits; and a heat index of 125 °F or more is something to act on now.