Articles

Percentage difference divides by the average and has no direction. Percentage change divides by the old value. See when to use each, with examples.

Percent error compares a measurement with the accepted value. Learn the formula, the signed version, and how it differs from percent difference.

Carry your drinking rate times the hours to the next source, plus a reserve. See how heat, climbing and weight change how much water to bring.

Base weight is your pack minus food, water and fuel. Learn how to calculate it, what ultralight means, and where the heaviest gear hides.

Set a hike turnaround time before you start: subtract a safety buffer from daylight, then subtract your return time. Worked examples inside.

Naismith’s rule gives 1 hour per 5 km plus 1 hour per 600 m of climb. Learn how to turn any route into a moving time, then plan breaks and daylight.

One minute of CD stereo is 10.58 MB, or 10.09 MiB. Learn the audio file size formula, bitrate math, MB vs MiB, and how compression shrinks files.

Divide 60000 by the BPM to get a quarter note in milliseconds. Learn eighth, dotted and triplet delay times, plus LFO rates in Hz.

A cent is one hundredth of a semitone. Learn the 1200 x log2 formula, just vs equal-tempered intervals, and how to turn cents back into hertz.

A4 is 440 Hz, middle C is 261.63 Hz, and every octave doubles the pitch. Learn the equal temperament formula, MIDI numbers, and note wavelengths.