Weather, earth and fun calculators
Moon phase, wind chill and heat index, altitude and air pressure, carbon footprint, rainwater harvesting, and star-sign and numerology tools labelled as entertainment.
7 calculators, 39 checked worked examples.
Sky
Weather
- Air pressure at altitude and boiling point calculator
Air pressure at altitude from the standard atmosphere, with temperature, air density and the boiling point of water, or the altitude for a given pressure.
- Wind chill, heat index and dew point calculator
Wind chill and heat index calculator: the feels-like temperature from the NWS formulas, plus dew point, frostbite risk and heat-stress level.
Environment
- Personal carbon footprint calculator
Carbon footprint calculator: yearly tonnes of CO₂e from driving, flights, train and bus, home electricity and diet, using UK government emission factors.
- Rainwater harvesting calculator
Rainwater harvesting calculator: yearly litres or gallons a roof collects from its area, rainfall and efficiency, and the share of household use it covers.
Fun
- Life path number calculator (numerology)
Life path number calculator: a birth date reduced to a numerology number from 1 to 9, or the master numbers 11, 22 and 33, with every step shown.
- Zodiac sign calculator: star sign and Chinese zodiac
Zodiac sign calculator: your star sign and its element from a birth date, plus the Chinese zodiac animal, element and yin or yang. For entertainment.
How to choose a earth & fun calculator
Separate environmental estimates from forecasts
Wind chill, heat index and pressure tools apply formulas to conditions you supply; they do not fetch a local weather forecast. Select the correct temperature scale, humidity and wind units, and read the model's valid range. Moon-phase estimates describe a lunar cycle, while visibility at a particular location depends on additional conditions. Check an authoritative local forecast or observation when planning an outdoor activity or making a safety decision.
Wind chill and heat index · Air pressure and altitude · Moon phase
Use environmental totals as scenarios
Rainwater harvesting combines roof area, rainfall and an efficiency allowance. Consistent area and depth units are essential because their product is a volume. Carbon-footprint estimates depend on the factors and activities selected, so compare scenarios using the same assumptions. These estimates help explain the arithmetic but cannot replace a local design assessment or a measured inventory. Read the sources and sensitivity to inputs before treating a total as a precise personal footprint.
Entertainment tools have a different purpose
The zodiac and numerology pages are labelled entertainment. They turn a date or name into a conventional category and do not provide scientific predictions about personality, compatibility or future events. Keep those activities separate from the physical models in this hub. If you need an exact elapsed age or a date interval, the date-and-time calculators explain their calendar conventions and show the relevant arithmetic.