Science & Education

Plot an acid–base titration curve, mark buffer and equivalence landmarks, and explain the Henderson–Hasselbalch steps.

Math & Numbers

Compute the total, sensible, and latent capacity of an air-handling-unit (AHU) coil from the entering/leaving air state and the dry-air mass flow ṁ_da. Total capacity Qt = ṁ_da·(h1 − h2); sensible capacity Qs = ṁ_da·cp_ma·(T1 − T2) with cp_ma ≈ 1.006 + 1.86·W [kJ/(kg da·K)]; latent capacity Ql = Qt − Qs; Sensible Heat Ratio SHR = Qs / Qt. Each state is described by dry-bulb T plus one humidity input (relative humidity φ, or humidity ratio W); W is derived from the Magnus saturation fit when RH is supplied, and enthalpy h = 1.006·T + W·(2501 + 1.86·T) [kJ/kg da]. Signed result — works for cooling or heating coils.

Math & Numbers

Compute complex admittance Y = 1/Z = G + jB for series or parallel RLC circuits: G = R/|Z|², B = −X/|Z|². Returns conductance, susceptance, magnitude and phase angle. Supports any subset of R/L/C.

Math & Numbers

Calculate the Rankine active earth pressure on a smooth vertical wall backfilled with cohesionless soil. K_a = tan²(45°−φ/2). Optional uniform surcharge q. Returns the base pressure p₀, the total force P, and the resultant height.

Finance

Calculate credit card cash back rewards across multiple spending categories. Enter categories as 'name, monthly spend $, cash back %' per line. Shows monthly and annual cash back per category, total rewards, effective cash-back rate, and a comparison against a flat-rate card.

AI Tools

Generate up to 10 creative domain names with AI and filter out already-registered ones via DNS + RDAP.

Games

Classic 2048. Arrow keys or swipe to slide and merge equal numbers. Each valid move spawns a tile; score accumulates from merges. 4×4 / 5×5 / 6×6 boards, pick a goal tile.

Data Analysis

Compute conversion-rate or mean differences, 95%/99% confidence intervals, two-sided p-values (Z-test for proportions, Welch t for continuous metrics), lift, sample size for 80%/90% power, recommended experiment days, plus sequential-testing and Bonferroni multiple-comparison warnings.

Text Processing

Turn a phrase into an acronym or initialism. Choose contributing words, which letter(s) to take, the separator, and the case.

Data Visualization

See the Central Limit Theorem in action: draw samples from a non-normal source distribution (uniform, exponential, Poisson, or Bernoulli), plot the histogram of sample means, and overlay the predicted Normal curve N(μ, σ²/n). Compare empirical vs theoretical mean and standard error, and watch convergence tighten as the sample size grows.

Geography

Geocode an address into normalized place details, latitude, and longitude coordinates

Security

Parse an X.509 SSL/TLS certificate (paste PEM or upload .pem/.crt) and inspect subject, issuer, validity period with expiry status, public key, signature algorithm, serial, SANs, key usage and fingerprint. Like openssl x509 -text, visualised. Runs locally.