Sectional
Outdoors, aviation, and archery calculators
Arrow setup, the crosswind on a runway, a ski or snowboard length to start from, a golf club length from a published chart, the energy a bullet carries, the drop downrange, pressure altitude from the altimeter setting, and a bike tire pressure read from a published chart.
Arrow Speed Calculator
Arrow speed, FOC, and kinetic energy calculator. Chronograph speed or an IBO estimate, plus front-of-center and foot-pounds.
Crosswind Calculator
Crosswind component calculator. Runway, wind direction, and wind speed give the crosswind and the headwind or tailwind.
Ski Size Calculator
Ski length calculator from height, weight, and ability. A chin-to-head heuristic from retailer fit charts, not a DIN setting.
Snowboard Size Calculator
Snowboard length calculator from height, weight, and riding style, with a wide-board flag at a US men’s 11 boot.
Bullet Energy Calculator
Bullet energy calculator. Foot-pounds, momentum, joules, and an optional Taylor KO factor, in grains or grams.
Ballistic Calculator
Ballistic calculator for drop, drift, velocity, and energy. Point-mass G1 and G7 drag. No reloading data.
Density Altitude Calculator
Density altitude calculator from elevation, altimeter setting, temperature, and humidity. ISA atmosphere, shared with the ballistic model.
Bike Tire Pressure Calculator
Bike tire pressure from Frank Berto’s published 15% tire-drop chart. The fill pressure stays under the tire maximum, the rim maximum, and 72.5 psi on a hookless rim.
Golf Club Length Calculator
Golf club length from height and wrist-to-floor, using the Wishon fitting chart and GolfWorks standard lengths. A static starting point.
Pressure Altitude Calculator
Pressure altitude from field elevation and the altimeter setting, or from station pressure. For flight-planning practice. Not a substitute for the POH or AFM.
Recoil Calculator
Free recoil energy estimate using the SAAMI method. Not felt recoil. Does not account for muzzle brakes, suppressors, or stock design. Not a reloading manual — never use this page to select powder charges or develop loads. Follow SAAMI / manufacturer pressure and firearm manuals.
How these calculators work
Front-of-center is the AMO measurement: how far the balance point sits ahead of the shaft’s midpoint, as a percent of shaft length. Kinetic energy uses Easton’s identity, grain weight times speed squared divided by 450,240. The speed estimate scales from the IBO test condition, 70 pounds, 30 inches, 350 grains. A chronograph still wins.
Crosswind is wind speed times the sine of the angle between the wind and the runway heading. Headwind is the cosine. Runway 27 is heading 270. Wind is the direction it comes from.
The ballistic calculator is a flat-fire point-mass model with BRL G1 and G7 drag. It reports drop, drift, velocity, and energy. It does not model spin drift, and it does not give a powder charge or a reloading recipe. Energy at one velocity, with no trajectory, is the bullet energy calculator beside it. Free recoil is the SAAMI free-body figure. It is not felt recoil and not a load. Pressure altitude is the FAA 1,000-foot rule or the NOAA station-pressure formula. Density altitude uses the same moist-air density, then inverts the ISA standard atmosphere. Humidity enters as virtual temperature. A 7,000 ft, 18°C, standard-pressure example is the check against the FAA 120-foot rule of thumb.
The bike tire calculator reads Frank Berto’s published 15% tire-drop chart at the wheel load and the measured width. It does not fit a new formula. The fill pressure stays at or under the tire maximum, the rim maximum, and 72.5 psi on a hookless rim. A knobby mountain-bike tire is not given a number. Golf club length reads the Wishon height and wrist-to-floor chart, then the GolfWorks standard lengths. A height that is not on the chart is not given a made-up length.