HVAC Duct Calculator: Duct Sizing, Pressure Loss, CFM

Compound Interest and Savings Growth Calculator

mangudai/compound-interest-savings-calculator

Project savings growth with compound interest and regular contributions. Get a full period-by-period schedule of balance, contributions, and interest, or a summary per scenario. Runs offline with exact decimal math, no API key. Compound daily to yearly and compare multiple plans.

Date and Age Calculator

mangudai/date-age-calculator

Calculate age from a birth date, the number of days between two dates, or add and subtract years, months, weeks and days. Every row returns years, months, days, running totals, weekdays, the next birthday and the zodiac sign. Runs fully offline with no API key.

Helical spring calculator from plain text: rate, stress, safety factors, solid and free length, buckling, surge and fatigue for compression, extension and torsion springs, and compression spring design from loads and space.

Bolted joint calculator from plain text: preload and tightening torque, bolt and joint stiffness, bolt load, safety against yield, separation, fatigue and slip, bolt length, and bolt sizing. Metric and inch, ISO, SAE and ASTM grades.

ASCE 7-16 design loads from plain text: wind pressures on walls and roofs and base shear by the directional procedure, roof snow loads with unbalanced loads and drifts at steps and parapets, and LRFD and ASD load combinations.

A/B test significance, t-tests, ANOVA, chi-square, correlation, linear and logistic regression, sample size and more, with plain-language results, effect sizes, assumption checks and charts. From numbers, CSV, Excel, Google Sheets or an Apify dataset. Checked against R. For AI agents.

Spur gear calculator from plain text: AGMA bending and contact stresses, safety factors, geometry factor J from the generated tooth, Kv, Ks, Km, life and reliability factors, tooth geometry, forces, rated power, and module sizing.

Earthwork volumes from plain text: cut and fill from cross-sections with the mass diagram and shrinkage, grid (borrow-pit) volumes and the balanced grade, and pits, trenches and stockpiles, with truck loads and a chart.

Heat exchanger rating and sizing (effectiveness-NTU, LMTD and F, steam and refrigerants), pipe and tank insulation heat loss and thickness (ASTM C680), and wall U-values (ISO 6946). JSON in, numbers and charts out. For AI agents.

Refrigerant charge checks from plain text: superheat and subcooling from gauge readings with the piston or TXV target and an add, recover, restriction or airflow verdict, target superheat, pressure-temperature charts for 15 refrigerants including R-410A, R-454B and R-32, and line set charge.