Math & Numbers
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.
convolution-integral-calculatorDesign
Resolve any hex color to its nearest CSS named color with true CIEDE2000 ΔE distance, then browse the whole color family it belongs to.
css-color-name-resolverEducation
Convert A ↔ %T ↔ T with A = −log₁₀(T) and %T = 100·T; returns all three representations for spectrophotometry work.
absorbance-transmittance-converterEducation
Convert cell density across cells/L, cells/mL, cells/µL, 10³/µL, 10⁶/mL, 10⁹/L and 10¹²/L for cell culture and hematology reports.
cell-density-unit-converterDesign
Layered radial-gradient "mesh" backgrounds with conic underlays, blend modes, grain and seeded layouts — live preview, CSS and Tailwind export.
css-gradient-mesh-generatorMedia
Add a subtle text watermark to one image or every supported image in a ZIP, at all, random, or chosen perimeter positions with automatic dark/light local contrast.
adaptive-12-point-hidden-watermarkMedia
Partially cover matching low-contrast text watermarks at all, random, or selected perimeter positions using a local Canvas patch.
adaptive-12-point-watermark-cover-restorerHealth
Compare Mifflin-St Jeor, original and revised Harris-Benedict, Schofield (FAO/WHO/UNU), and Katch-McArdle BMR equations side by side with mean and spread in kcal/day. Not medical advice.
basal-metabolic-rate-extHealth
Compute CO = V × (T_b − T_i) × 60 × 1.08 / A from a thermodilution curve, with optional cardiac index from BSA (normal 2.5–4.0 L/min/m²). Not medical advice.
cardiac-output-thermodilutionMedia
Generate exact A=440, A=432, or custom equal-tempered reference notes and practice scales.
audio-tuning-reference-generatorHealth
Trophic pyramid from producer energy and transfer efficiency: per-level energy, % of base, losses, and why energy pyramids stay upright.
biomass-pyramidHealth
Annual personal CO₂e from diet, energy, fuels, flights, transit, and waste with per-category breakdown and target comparisons.
carbon-footprint-calculator