Generalized pairwise-merge CRT for 2–20 congruences: coprime moduli give the product modulus, consistent non-coprime moduli give the lcm, inconsistent systems are rejected.

Math & Numbers

Assignment Problem Solver (Hungarian Algorithm)

Textbook Hungarian algorithm for 2–8 × 2–8 assignment problems: row/column reductions, augmenting-path zero matching, König line covers, and substitution-verified optimal assignments.

Math & Numbers

Permutation / Combination / Subset Generator (With Repeats)

Deduplicated, lexicographic permutations / combinations / subsets of up to 12 items with exact multiset counts; display capped at 200 entries.

Math & Numbers

Critical Path Method Calculator (CPM)

Activity-on-node CPM: ES/EF/LS/LF, total float, project duration, and every critical path; cycles and unknown predecessors are rejected.

Math & Numbers

Boolean Algebra Simplifier (Karnaugh Map)

Minimal SOP via Quine–McCluskey with essential prime implicants, exact minimum cover, Gray-coded Karnaugh map, and full-assignment verification.

Math & Numbers

Convolution Integral Calculator (Numeric)

Numeric (f*g)(t) = ∫ f(τ)g(t−τ)dτ by composite Simpson, in causal or direct-window mode, at up to 8 output points.

Finance

Betting Odds Calculator

Convert odds between decimal, fractional, and American formats with implied probability, plus parlay combination odds and no-vig fair-odds calculation.

Math & Numbers

Angular Velocity Converter (rad/s / rpm / deg/s / Hz)

Convert angular velocity (angular speed) between radian per second (rad/s, SI base), revolutions per minute (rpm = 2π/60 rad/s), degrees per second (deg/s = π/180 rad/s), and hertz (Hz, used as revolution per second = 2π rad/s). Converts via rad/s to the target unit and lists all four equivalents. Note: 1 Hz in angular-frequency context means one full revolution per second, so 1 Hz = 2π rad/s ≈ 6.283185307 rad/s. Reference: vinyl LP 33⅓ rpm ≈ 3.49 rad/s, car engine idle ~800 rpm ≈ 83.8 rad/s.

Finance

Compound Interest Contribution Timeline Tutor

Explore how contributions, compounding, fees, and inflation shape investment growth year by year.

Math & Numbers

Uniform Corrosion Rate Calculator (Weight Loss)

Uniform corrosion rate by weight loss per ASTM G1: CR (mm/a) = 87.6 × ΔW / (ρ × A × t), with ΔW in mg, ρ in g/cm³, A in cm², t in hours. Also reports mpy (mils/year = mm/a × 39.37) and an indicative NACE-style carbon-steel rating (excellent/good/fair/poor). Used for immersion tests and coupon exposure.

Math & Numbers

Bulk Density & Porosity Calculator

Bulk density and porosity for granular or porous materials. Three-way solver: pick the unknown (ρ_bulk, m, or V) and supply the other two. ρ_bulk = m/V_bulk. Optionally enter the true particle density ρ_true to compute porosity ε = 1 − ρ_bulk/ρ_true, plus relative density against water. SI units (kg, m³, kg/m³).

Math & Numbers

Air Changes per Hour (ACH, n = Q/V)

Compute the air change rate (ACH / n) of a room from the outdoor supply airflow Q and the room volume V: n = Q/V (1/h). Three modes: solve ACH (given Q and V), solve airflow (given n and V), or solve volume (given n and Q). Flow in m³/s/m³/h/CFM, volume in m³/ft³/L. Also reports the well-mixed single-zone purge time to reach a target residual fraction ε (default 1%): t = −ln(ε)/n hours.