Astronomy Advanced Calculators
Astro-Physical Settings
Explore Additional Utilities
Engine power ↔ hull speed — planing vs displacement
Estimate maximum displacement hull speeds (LWL formula) or calculate planing hull speeds using Crouch's classic marine formula.
Narcosis depth — nitrogen % ↔ equivalent air depth
Calculate Equivalent Narcotic Depth (END) and Equivalent Air Depth (EAD) for nitrox and trimix gas breathing mixtures.
Flash Guide Number Calculator
Solve the photography flash equation to find guide numbers, aperture, subject distance, or ISO speed for perfect manual flash exposures.
Navy Body Fat Estimator
Estimate body fat percentage using standard US Navy circumference measurements.
APR ↔ APY Yield Converter
Convert interest rates between Annual Percentage Rate (APR) and Annual Percentage Yield (APY).
Unix Epoch Converter
Convert Unix epochs (seconds/milliseconds) to human-eye standard DateTimes, and transform local dates to Epoch times.
Magnetic Declination
Estimate compass alignment values and offset angles between magnetic north and true north.
Paper Size Comparer
Convert standard paper formats (A4, Letter, Legal, A3) in mm/inches and visually compare overlap.
Length Converter
Convert between meter, kilometer, centimeter, mile, yard, foot, inch, and more.
Angular Motor Rotation
Determine crankshaft engine RPM, radian ratios, and angular physical velocities.
Duration Converter
Convert time intervals seamlessly between weeks, days, hours, minutes, and seconds.
Numerical aperture ↔ acceptance angle — fiber coupling
Determine light coupling capabilities, supported modes, V-numbers, and acceptance cone widths for optical optical fibers.
Injector duty cycle — fuel demand ↔ injector size
Match fuel injector sizes (cc/min or lb/hr) with horsepower targets, number of cylinders, and Brake Specific Fuel Consumption (BSFC) targets.
Cooling & HVAC Power (BTU/h ↔ W)
Compare heating, cooling, and air conditioning power capacities with corresponding watt ratings.
Generator sizing — equipment load ↔ kVA needed
Estimate generator apparent power capacity requirements by summing dynamic equipment active and reactive loads.
pH Acid/Base Index
Evaluate hydrogen ion concentrations and check acidic or alkaline levels using pH logarithmic scales.
Screw gauge ↔ mm diameter — imperial vs metric screws
Cross-reference standard wood screw gauges with thread diameter in millimeters and inches for pre-drilling and pilot holes.
Tidal Rule of Twelfths Calculator
Estimate hourly tide heights and flow volumes between high and low tide periods using the standard maritime rule.
Engineering Slope & Gradients
Compare elevation grades, percentage slopes, and corresponding degrees.
Acoustic Decibel Ratio
Formulate sound logarithmic decibel power ratios and acoustic pressure variations.