• Hiking Water Intake Calculator
    Estimate how much water to carry on a hike. Enter duration, base rate and weather to get liters, milliliters, ounces and bottle count.
  • Layover / Connection Time Calculator
    Calculate your flight layover or connection time in minutes between arrival and next departure, and check if it beats the minimum connection time.
  • Flight Time Calculator
    Estimate flight duration from distance and cruise speed, plus a taxi/climb overhead. Get gate-to-gate hours and minutes for any route, any units.
  • Road Trip Fuel Cost Calculator
    Estimate the fuel cost of any road trip. Enter distance, MPG, and price per gallon to instantly see total fuel spend and gallons used.
  • Jet Lag Recovery Time Calculator
    Estimate how many days you need to recover from jet lag based on time zones crossed and travel direction (eastward vs westward).
  • Travel Budget Calculator
    Plan your trip budget instantly. Add flights, hotel, food, activities & transport to get total cost, cost per person, and cost per day.
  • Gallons of Gas for Trip Calculator
    Calculate how many gallons of gas you need for a trip from distance and MPG, plus estimated fuel cost. Fast, free road-trip fuel planner.
  • Hiking Time Calculator
    Estimate how long a hike will take using Naismith's Rule: time from distance, walking speed, and total ascent. Free, instant trek planning tool.
  • Lat Long Distance Calculator
    Enter two latitude and longitude pairs to compute the great-circle distance between points on Earth. Quick, accurate results for mapping and GIS.
  • Boiling Point Altitude Calculator
    Find the boiling point of water at any altitude in °C and °F, plus atmospheric pressure. Free, instant boiling point altitude calculator.
  • Scuba Diving Bottom Time Calculator
    Estimate your available scuba dive bottom time from tank volume, start/reserve pressure, depth and SAC rate. Metric units, keeps a safety reserve.
  • Great-Circle Distance and Azimuth Calculator
    Compute the shortest great-circle distance (km, miles, nautical miles) and initial azimuth bearing between two latitude/longitude points using the haversine formula.
  • Backpack Weight Calculator
    Calculate your backpack weight as a percentage of body weight and see your recommended maximum pack load for safe, comfortable hiking.
  • Great-Circle Distance & Bearing Calculator
    Compute the great-circle (shortest) distance and initial compass bearing between two latitude/longitude points on a spherical Earth. Universal geodesy tool.
  • Altitude Air Pressure Calculator
    Calculate atmospheric air pressure at any altitude using the barometric formula. Get results in hPa, mmHg, and psi for any height above sea level.
  • Probability of Encountering a Fatal Airplane Accident
    Compute the cumulative probability of at least one fatal airplane accident if you fly daily for many years, using per-flight fatal-accident rates.
  • Hammock Hang Calculator
    Calculate hammock anchor height, center sag and strap tension from distance, hang angle and body weight. Get the ideal 30-degree hang fast.
  • Tent Size Calculator
    Calculate the right tent floor area for your group. Enter number of people and comfort level to get recommended m² and square footage instantly.
  • Sunscreen Calculator
    Calculate how much sunscreen to apply (2 mg/cm²), how often to reapply, and how long your SPF protection lasts based on baseline burn time.