Math & Numbers

Calculate the infinite-slope factor of safety: FS = c'/(γ·z·cosβ·sinβ) + tanφ'/tanβ. Supports dry slopes and seepage parallel to the slope. Returns FS and a stable/marginal/unstable classification.

Media

Edit subtitle timing, shift cues, repair overlaps, calibrate CPS, wrap long lines, and export SRT, VTT, ASS, or TTML.

Math & Numbers

Calculate the maximum shear stress τ_max = V·Q/(I·b) at the neutral axis of a beam section. Supports rectangle (1.5V/A), solid circle (4V/3A), hollow tube, and I-beam (exact V·Q_web/(I·tw)). Also returns the average shear stress V/A for comparison.

Math & Numbers

Calculate the maximum bending moment M_max, maximum shear force V_max and support reactions for a simply supported beam under a uniformly distributed load, a mid-span point load, or a point load at an arbitrary position. UDL: M_max = qL²/8; mid-span: M_max = PL/4; offset: M_max = P·a·b/L.

Math & Numbers

Calculate the critical (resonance) speed of a rotating shaft using the single-DOF rotor model. ω_n = √(k/m), n_cr = (60/2π)·√(k/m) rpm. Also returns the natural frequency f_n in Hz.

Math & Numbers

Calculate the power transmitted by a rotating shaft. P = T·ω = 2π·n·T/60. Solve power from torque and speed, or torque from power and speed. Supports W/kW/hp.

Math & Numbers

Calculate the elastic potential energy and force of a spring in compression or extension. U = ½·k·x², F = k·x. Solve energy from displacement, or displacement from energy.

Math & Numbers

Calculate the stiffness (spring rate) of a cylindrical helical compression/extension spring. k = G·d⁴ / (8·D³·n) in N/mm. Includes shear-modulus presets for common spring materials.

Finance

Convert between hourly, monthly, and annual salary. Enter any one figure and get the other two, with customizable hours per week, weeks per year, and overtime multiplier. Shows paycheck estimates for weekly, biweekly, semimonthly, and monthly pay periods.

Finance

Calculate student loan repayment with an optional grace period and subsidized/unsubsidized interest. Unsubsidized loans accrue interest during the grace period that capitalizes into principal; subsidized loans do not. Shows monthly payment, total interest, total repayment, a balance curve, and a yearly breakdown.

Finance

Solve for the monthly contribution needed to reach a savings goal (with interest and compounding), or for the time required to reach the goal with a fixed monthly deposit. Optional inflation adjustment. Uses monthly compounding rollup.

Media

Reduce broadband noise with a spectral filter chain