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CalcSpan vs The Body Index

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

CalcSpan compared with The Body Index
DetailCalcSpan logo CalcSpanThe Body Index logo The Body Index
What it doesDate, deadline and time calculators with visible assumptions and sources Free body-metric calculators with no accounts or ads in results
StageNot given Not given
FoundedNot given Not given
Based inUS Not given
Pricing modelFree Free
PricingNot given Not given
Key features
  • 184 calculators across 53 categories
  • Shows counting rules and assumptions with each result
  • Local-first processing with no data sent to servers
  • Holiday and weekend calendar selection
  • Business day counting
  • Date arithmetic (add or subtract days, weeks, months, years)
  • Sleep cycle planner with NIH-based 80-100 minute cycles
  • Time zone conversion with DST handling
  • Save results as images or add to calendar
  • Schengen visa 90/180 day rolling window auditing
  • Open source formulas on GitHub
What makes it different
  • Shows the source and counting rule beside every answer
  • No sign-up or account required to use any calculator
  • All inputs stay in your browser for privacy
  • Comprehensive coverage across 53 life and work categories
  • Higher-risk calculators include prompts to verify with professionals
  • Calculators for metrics beyond BMI that major sites haven't adopted
  • Open source formulas validated against peer-reviewed research papers
  • All code available under MIT license for verification and reuse
  • Free embeddable widgets with attribution for other websites
Community votes00
DR (Domain Rating by Ahrefs)Not checked yet no change since last checkNot checked yet
Trust Flow (Majestic)00
Citation Flow (Majestic)00
Referring domains (Majestic)00

4 details filled in for both companies.

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