Free, accurate calculators — verified against official sources

Every calculator on CalcMeadow documents its formula and cites the official source it was verified against, so you can trust the number you get.

• Chronological Age Calculator

  Compute exact chronological age in years, months, and days for speech-language pathology and educational testing.

• 13th Month Pay Calculator (Philippines)

  DOLE-compliant 13th month pay computation, including prorated pay for mid-year hires and unpaid absences.

• SSS Contribution Calculator 2026

  Monthly SSS contribution under the 15% rate: MSC table, employee/employer shares, EC, and WISP — from official SSS circulars.

• Take-Home Pay Calculator (Philippines)

  Net monthly salary after SSS, PhilHealth, Pag-IBIG, and BIR withholding tax under the TRAIN Law.

• VTU CGPA to Percentage Calculator

  Convert VTU CGPA to percentage using the official VTU formula: (CGPA − 0.75) × 10.

• Nigeria Income Tax Calculator 2026

  Personal income tax under the Nigeria Tax Act 2025 (effective January 2026), including rent relief.

• Asian BMI Calculator

  BMI with WHO Asian-Pacific cutoffs — the standard BMI categories don't apply equally to Asian populations.

• Chicken Coop Size Calculator

  Coop and run square footage, nest boxes, and roost length from university extension guidelines.

• Chicken Feed Calculator

  Daily to yearly feed for layers, broilers, and chicks — plus bag duration and monthly cost.

• Bee Sugar Syrup Calculator

  1:1 and 2:1 sugar syrup by weight: sugar and water amounts for spring feeding or fall stores.

• Wood Shrinkage Calculator

  Board width change across moisture content, using USDA Wood Handbook shrinkage data for 20 species.

• Epoxy Resin Calculator

  Epoxy volume for pours and coats, with resin/hardener split by mix ratio and a waste allowance.

• 3D Printer Electricity Cost Calculator

  Electricity cost per print from wattage, print time, and your kWh rate (EIA average preset).

• eBay Fee Calculator

  Final value fees, per-order fee, and real profit — eBay's official 2026 rates by category.

• LLM API Cost Calculator (Cascade Savings)

  Monthly LLM API spend and how much cascade routing saves, using official 2026 GPT, Claude, Gemini, and DeepSeek prices.