Document Tools

Convert Markdown files to PDF documents with proper formatting, syntax highlighting, and styling

Format Conversion

Convert logfmt (key=value) to JSON or JSON back to logfmt, with quote escaping, number/boolean coercion, and duplicate-key handling.

Health

Estimate single-pool Kt/V (spKt/V) for a hemodialysis session with the Daugirdas second-generation formula: Kt/V = −ln(R − 0.008·t) + (4 − 3.5·R) × UF / W, where R = Post-BUN/Pre-BUN, t = treatment time (h), UF = ultrafiltration volume (kg), W = post-dialysis weight (kg). The first term captures urea removal and generation; the second corrects for volume contraction. KDOQI target: spKt/V ≥1.2 per session (minimum delivered dose) for conventional thrice-weekly hemodialysis, target ~1.4. Requires post-dialysis BUN drawn by slow-flow/stop-pump technique. Derived from Daugirdas JT, J Am Soc Nephrol 1993. Valid for intermittent hemodialysis; not for peritoneal dialysis or CRRT/SLED. Not medical advice.

Health

Calculate the loading dose required to rapidly reach a target plasma concentration: LD = Css · Vd / F, where Css is the target concentration, Vd is the volume of distribution, and F is bioavailability (1 for IV, <1 for oral). A loading dose achieves Css essentially immediately (one-compartment IV bolus) instead of waiting 4–5 half-lives for accumulation. For oral loading, divide by F. Maintenance dosing (MD = Css·CL·τ/F) must follow to sustain the concentration. Loading doses are hazardous for narrow-therapeutic-index drugs (digoxin, theophylline, antiarrhythmics) — clinical judgement required. Optional body-weight input converts the result to mg/kg. Not medical advice.

Development

Run a safe, curated set of Lodash helpers on JSON input.

Health

Calculate the maintenance dose that holds the average steady-state concentration at a target value: MD = Css,avg · CL · τ / F, where Css,avg is the target average concentration, CL is clearance, τ is the dosing interval, and F is bioavailability (1 for IV, <1 for oral). Derived from steady-state mass balance (rate in = rate out): the dose per interval equals the amount cleared over one interval, corrected for bioavailability. Targets the AVERAGE Css,avg — the peak Cmax,ss and trough Cmin,ss fluctuate around it depending on t½ and τ. Valid only for linear pharmacokinetics with fixed dose and interval — NOT for Michaelis-Menten drugs (phenytoin). Optional body-weight input converts the result to mg/kg. Not medical advice.

Math & Numbers

Convert luminance between cd/m² (nit, SI base), stilb (1 = 10000 cd/m²), cd/ft² (1 = 10.76391 cd/m²), foot-lambert (1 = 3.426263 cd/m²), apostilb (1 = 0.31831 cd/m²), lambert (1 = 3183.099 cd/m²), and millilambert (1 = 3.183099 cd/m²). All non-SI units except stilb carry a 1/π factor from Lambertian diffuse-emission assumptions. Reference values: LCD display ≈ 200–300, comfortable eye level ≈ 1000, sun surface ≈ 1.6×10⁹ cd/m².

Math & Numbers

Convert luminous intensity between candela (cd, SI base, = 1/683 W/sr at 540 THz), millicandela (1 = 0.001 cd), and candlepower (1 = 0.981 cd, obsolete standard candle). Converts via candela to the target unit and lists the equivalent value in all three units for reference. Reference values: indicator LED ≈ 5–20 mcd, flashlight ≈ 100–1000 cd, car headlight high beam ≈ 75000 cd.

Math & Numbers

Convert kinematic viscosity (ν = dynamic viscosity / density) between m²/s (square metres per second, SI base), cSt (centistokes, 1 cSt = 1e-6 m²/s = 1 mm²/s), and ft²/s (square feet per second, 1 = 0.09290304 m²/s). Converts via m²/s to the target unit and also lists the equivalent value in all three units for reference. Reference values: water 20°C ≈ 1.004 cSt, SAE 30 oil ≈ 300–400 cSt at 40°C.

Math & Numbers

Calculate the mechanical advantage of a lever and its output force. MA = L_in / L_out, and by moment balance F_out = F_in · MA. MA > 1 saves force; MA < 1 saves distance.

Utilities

Predict the Lewis dot structure, valence electrons, central atom, lone pairs, and VSEPR geometry (linear / trigonal / tetrahedral / …) of a covalent molecule.

Health

Estimate your lean body mass (LBM) from sex, age, weight and height using three clinical formulas side by side, with derived body-fat percentage.