Psychology & Research Calculator
Standardized psychometric calculators, sample size tools, and statistical transformations for behavioral science, clinical studies, and empirical research analysis.
Sample Size Calculator
Determine required sample sizes for representative surveys using Cochran’s or Yamane’s formulas, adjusted for finite population sizes.
Survey Margin Parameters
Calculated Target Sample Sizes
Methodological Note
Cochran's Formula uses normal distribution Z-critical statistics (Z=1.960) adjusted for expected response variance.
Selecting 50% Response Distribution guarantees maximum possible variance, ensuring your calculated sample size is large enough to achieve the target confidence regardless of the true proportions.
Explore Additional Utilities
Kiln temperature — cone number ↔ degrees Celsius
Map pyrometric Orton cones to exact kiln temperature equivalents at fast or slow heating rates.
Frequency ↔ Wavelength (Sound)
Convert between sound frequency and wavelength in air or water, considering temperature and medium sound speed variations.
Heel angle ↔ righting moment
Calculate heel angle, righting arm (GZ), righting moment, and sailboat stability from displacement, vertical center of gravity, and wind force.
Watch case size — mm diameter ↔ lug width
Analyze watch case diameter proportions, lug-to-lug spans, and find the corresponding standard strap lug-width sizes.
Swimming Pace & Yardage Converter
Convert swim splits and paces between per-100m, per-100 yards, and overall distances with custom pool sizes.
Wind Chill Calculator
Determine the feels-like wind chill index from ambient air temperature and wind speed.
Muzzle velocity — fps ↔ m/s ↔ km/h
Convert velocities between fps, m/s, and km/h. Calculate muzzle kinetic energy in Joules and Foot-Pounds.
Dye concentration — wax weight ↔ color chips needed
Determine dry color chips or fluid dye drops needed based on total wax weight and target color depth.
VO2 Max & Aerobic Capacity Estimator
Convert running race times or heart rates into VO2 Max estimates and aerobic fitness classifications.
Leather weight — oz ↔ mm thickness
Convert leather weights in ounces to exact millimeter or fractional inch thickness. View target usage categories.
Flow Rate Converter
Convert volumetric flow rates between cubic meters per second (m³/s), liters per minute (L/min), gallons per minute (GPM), and other flow units.
Power reserve — mainspring tension ↔ hours of run time
Compute total mainspring operational run time based on turns of wind, barrel capacity, and balance wheel beat rate demands.
Visual Acuity Converter
Convert visual acuity measurements between Snellen US (20/20), Snellen Metric (6/6), decimal, LogMAR, and Percentage systems.
Length Converter
Convert between meter, kilometer, centimeter, mile, yard, foot, inch, and more.
Safety glass thickness ↔ impact resistance rating
Calculate safety glass thickness requirements and impact resistance (Tempered vs. Laminated).
Cloud Base Height Estimator
Estimate cloud condensation levels and cloud base height based on temperature and dewpoint spreads.
Oxygen Saturation & PaO2 Converter
Convert blood oxygen saturation (SpO2) to partial pressure of oxygen (PaO2) using the clinical Severinghaus-Ellis model.
Carat weight ↔ grams
Convert between diamond or gemstone carats, metric grams, grains, and points of gem weight.
Varroa mite load — alcohol wash count ↔ treatment threshold
Input alcohol wash or powdered sugar shake counts to analyze parasite load percentage and check treatment recommendations.
Yarn Weight Converter
Convert yarn sizes across WPI (Wraps Per Inch), ply, and standard weight categories.