Convert a timestamp (RFC 3339, ISO 8601, HTTP-date or epoch seconds) to RFC 3339, HTTP-date, RFC 5322, basic ISO and epoch.

Decode a geohash to its center latitude/longitude, bounding box and the plus-or-minus error in degrees.

Head-on collision of two masses: velocities after impact, momentum and kinetic energy lost, elastic to perfectly inelastic.

Block on an incline: weight components, normal force, static friction limit, whether it slips, acceleration and slide time.

Thin lens or mirror equation: give two of focal length, object and image distance, get the third plus magnification.

Encode latitude/longitude as a geohash (1 to 12 characters) with the cell bounds, center and size in meters.

Area, perimeter and centroid of a lat,lon polygon using spherical excess on the WGS84 equal-area sphere.

Constant-acceleration motion: give any three of displacement, start speed, end speed, acceleration, time; get the other two.

Encode latitude/longitude as an Open Location Code (Plus Code) with its area bounds and a short local form.

Destination latitude/longitude and final bearing from a start point, initial bearing and distance (WGS84, Vincenty).

Convert a UTM (18T 585628 4511322) or MGRS (18TWL8562811322) reference to WGS84 latitude/longitude.

The eight adjacent geohash cells (N, NE, E, SE, S, SW, W, NW) for a geohash, wrapping at 180 degrees longitude.

Circular orbit speed, escape speed and period at an altitude or radius around the Sun, a planet, the Moon or a custom mass.

Convert WGS84 latitude/longitude to UTM (zone, band, easting, northing) and MGRS, with Norway/Svalbard zone rules.

Ellipsoidal (WGS84, Vincenty) distance and bearings between two points, compared with haversine on a sphere.

Decode a Plus Code (Open Location Code) to its area and center; recovers short codes near a reference point.

Blackbody radiation: Wien peak wavelength and frequency, Stefan-Boltzmann power per area, and total power for an area or sphere.

Snell's law: refracted angle between two media (names or indices), critical angle and total internal reflection check.

Convert American, decimal, fractional odds and probability; add the other side for margin, or your own chance for Kelly.

Special relativity: Lorentz factor, time dilation, length contraction, total and kinetic energy and momentum at a given speed.