Math & Numbers
Convert between Arabic numbers and Roman numerals with validation and detailed results
roman-numeral-converterMath & Numbers
Advanced scientific calculator with support for complex mathematical functions and expressions
scientific-calculatorMath & Numbers
Convert between different speed units (m/s, km/h, mph, knot, mach, etc.)
speed-converterMath & Numbers
Convert between different temperature units (Celsius, Fahrenheit, Kelvin, Rankine)
temperature-unit-converterDate & Time
Convert dates to and from RFC 2822 format
rfc-2822-converterDate & Time
Calculate work hours using start and end times
work-hours-calculatorMath & Numbers
Calculate Taylor series expansion for common functions
taylor-seriesFinance
Calculate sales tax and final price for purchases
sales-tax-calculatorMath & Numbers
(n−1)! ≡ −1 (mod n) ⟺ n is prime. Exact factorial residue for n ≤ 10⁷, Miller–Rabin cross-check, composite factorial law, optional running-products trace.
wilson-theorem-checkerMath & Numbers
Compute the discharge over a sharp-crested thin-plate weir. Rectangular (suppressed, no side contraction): Q = (2/3)·C_d·√(2g)·b·H^1.5. V-notch (triangular): Q = (8/15)·C_d·√(2g)·tan(θ/2)·H^2.5. b is the crest width, H the head over the crest (or over the vertex for a V-notch), θ the notch angle. If C_d is left blank it defaults to 0.611 for rectangular weirs (Rehbock/Francis typical value) and 0.58 for V-notch weirs. Crest width in m/cm, head in m/cm/mm; output in m³/s, L/s, L/min and m³/h.
weir-flow-calculatorMath & Numbers
Compute transformer or feeder voltage regulation from equivalent-circuit parameters: ΔU% ≈ (I·R·cosφ ± I·X·sinφ)/U·100. Returns both the approximate (linear) and exact (phasor) values; supports lagging, unity and leading power factor.
voltage-regulation-calculatorMath & Numbers
Calculate the force-amplification ratio and self-locking condition of a wedge mechanism. Ideal M = 1/tan(α), with friction M = 1/tan(α+ρ) where ρ = arctan(μ). Self-locking when α ≤ ρ (i.e. tan(α) ≤ μ).
wedge-angle-force-calculator