Calculators that actually
explain themselves.
22 fast, accurate tools across health, finance, construction, education, and developer workflows. Every formula sourced. Every result shown step-by-step. Files never leave your device.
- Privacy-first
- Sub-second loads
- Math always shown
- Open formulas
Featured tools
Hand-picked across health, finance, building, and dev — the tools that earn their place in your bookmarks.
TDEE Calculator
Calculate your Total Daily Energy Expenditure (TDEE) with Mifflin–St Jeor accuracy, then see your protein, carb, and fat targets for cut, maintain, or bulk.
Keto Macro Calculator
Get your exact ketogenic macros: under 20 g net carbs, 0.7–1.0 g/lb protein, the rest from fat. Built for cut, maintain, and lean-bulk modes.
Calorie Deficit Calculator
See exactly how long it takes to hit your goal weight at any deficit size. Built around the 3,500 kcal-per-pound rule with metabolic-adaptation correction.
Pregnancy Weight Gain Calculator
See your trimester-by-trimester healthy weight-gain range based on pre-pregnancy BMI. Backed by Institute of Medicine guidelines.
Peptide Dosage Calculator
Convert peptide vial mg, BAC water mL, and target dose mcg into precise insulin-syringe units. Supports BPC-157, TB-500, semaglutide, tirzepatide, and any custom peptide.
Mortgage + Extra Payment
See your monthly payment, total interest, and exactly how many years extra principal saves. Compare scenarios A vs B side-by-side.
Margin & Markup Calculator
Calculate gross margin, markup, profit, and selling price from any two inputs. Built for ecommerce and SaaS operators who need the answer in seconds.
Salary → Hourly
Convert annual salary to hourly, weekly, bi-weekly, or monthly pay. Supports custom hours/week and PTO weeks/year.
Browse by category
Six clusters. 22 tools. All free, all explained.
Finance
Mortgages, margins, salary, loans, investing — fast answers with the math shown.
All 5 finance tools →Health & Fitness
Macros, calories, weight, pregnancy, peptides — backed by primary research.
All 5 health & fitness tools →Construction & Home
Concrete, gravel, fence posts, solar — built for contractors and homeowners.
All 4 construction & home tools →Developer Tools
Practical calculators for builders — token costs, latency, conversions.
All 2 developer tools tools →Writers Tools
Manuscript formatting, ebook export, and writer-grade utilities for self-publishers.
All 1 writers tools tools →File Converters
Privacy-first, in-browser converters. Your files never leave your device.
All 2 file converters tools →Every formula. Every source. Public.
We follow Google's E-E-A-T standards. Each tool cites peer-reviewed papers, government guidelines, or vendor documentation. Reviewed annually. No black boxes.
Read methodology- 01Sourced. Every formula links a primary reference.
- 02Reviewed. Domain experts approve each tool annually.
- 03Open. Math is shown, not hidden behind a wall.
- 04Private. Converters run in your browser, not ours.
Pick a tool. Get an answer. Understand it.
Free calculators get you the number. Pro turns it into a plan.