Update
Source Citations Added for All Calculators
Every calculator now shows formula sources, methodology, and authoritative references for complete transparency.
Changelog
Track all updates, improvements, and new calculators added to CalcOnce. We continuously improve our tools to ensure accuracy and add new features based on user feedback.
NewUpdateFixData Update
New
New Statistical Calculators
Added P-Value Calculator, Confidence Interval Calculator, and enhanced Mean Median Mode Calculator with step-by-step solutions.
New
Math & Science Calculator Expansion
Added 15+ new math calculators including Pythagorean Theorem, Slope, Logarithm, Square Root, LCM, GCF, and Scientific Notation calculators.
New
Business Finance Calculators
Added Margin Calculator, Markup Calculator, Break-Even Calculator, and Margin vs Markup comparison tool for business owners.
New
Date & Time Calculator Suite
Launched comprehensive date/time calculators including Business Days, Meeting Planner, Countdown, and Moon Phase calculators.
Data Update
2026 Tax Bracket Updates
Updated Income Tax Calculator with official 2026 federal tax brackets and standard deductions.
Update
PayPal Fee Calculator Updated
Updated PayPal fee rates for 2026 including new Checkout and Invoicing fee structures.
Update
Mortgage Calculator Enhancement
Added property tax and PMI calculations to mortgage calculator with live FRED mortgage rate data integration.
Fix
Moon Phase Algorithm Accuracy
Fixed moon phase calculation to use UTC dates consistently, ensuring accuracy across all time zones.
Fix
Sunrise/Sunset NOAA Compliance
Updated sunrise/sunset calculator to use correct NOAA zenith angle (90.833°) for atmospheric refraction.
Stay Updated
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