Finance

Calculate annuity payments, present value, and future value

Text Processing

Remove zero-width and invisible characters from text

Text Processing

Convert between letters and numbers (A=1, B=2, … Z=26) with configurable separator and case, decode numbers back to letters, and compute the letter sum of any text.

Education

Simulate Wright–Fisher genetic drift across many replicate populations with mutation and selection. Visualize drift trajectories, the final-frequency distribution, heterozygosity decay Hₜ = H₀(1−1/2Nₑ)ᵗ, and run a Hardy–Weinberg chi-square test.

Media

Upload an STL, OBJ, GLB or glTF model: exact vertex/triangle counts, bounding-box dimensions, materials, animations and node tree, plus an interactive Three.js viewer (rotate, zoom, shaded/wireframe/normals).

Health

Calculate expected respiratory compensation PaCO₂ for metabolic acidosis: 1.5×HCO₃⁻ + 8 ± 2 mmHg. Classifies compensation as appropriate or flags mixed disorders. Derived from Albert 1967, Emmett 2016, LITFL, MDCalc. Not medical advice.

Health

Calculate the alveolar-arterial O₂ gradient to distinguish hypoxemia causes. PAO₂ = FiO₂×(P_atm−47) − PaCO₂/0.8; A-a = PAO₂ − PaO₂. Normal ≈ (Age+10)/4. Elevated → V/Q mismatch, shunt, diffusion impairment. Derived from StatPearls, LITFL, Cornell PICU, and Martin 1999. Not medical advice.

Health

Calculate the Absolute Neutrophil Count (ANC) = WBC × (segmented % + band %) / 100. Unit selectable: cells/µL or ×10⁹/L (1 ×10⁹/L = 1000 cells/µL). Adult reference ≥ 1500 cells/µL. Neutropenia risk strata: mild 1000–1500, moderate 500–1000, severe < 500 (agranulocytosis < 200) — high risk of serious infection, and febrile neutropenia is a medical emergency. Clinical uses: chemotherapy cycles typically require ANC ≥ 1500 to proceed and ≥ 500 for discharge from protective isolation; carbimazole/clozapine monitoring; congenital neutropenia workup. Neutrophilia > 7500 suggests bacterial infection, inflammation, steroids, or a myeloproliferative neoplasm. If only segmented % is reported, set band % to 0; if the instrument reports an absolute neutrophil count directly (NE#), this tool is not needed. Based on ASCO/IDSA neutropenia guidance, Boxer ASH 2012, and MDCalc. Not medical advice.

Format Conversion

Convert pasted WireGuard or OpenVPN client text into Mihomo/Clash YAML or sing-box JSON with secret-field diagnostics; do not share private keys

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.