About DateSolver

DateSolver is a free collection of date calculators run by Storija d.o.o., a Croatian company, since 2026. Every calculator runs in your browser. Your inputs never leave your device. There is nothing to install and no account to create.

We built DateSolver because calendar math is harder than it looks. Leap years, daylight saving time, observed holidays, and ISO week numbering all introduce edge cases that quick mental math gets wrong. Every page on this site uses the date-fns library, which handles those edge cases correctly.

Questions, bug reports, or feature ideas? Email hello@date-solver.com.

Company

DateSolver is operated by Storija d.o.o.
Office: Dr. Franje Tuđmana 20, 48260 Križevci, Croatia (EU)
VAT: HR75982059725
Founder: Marco Slavecki

Tools we offer

• Date Calculator. Days between dates or add/subtract days.
• Age Calculator. Find your exact age in years, months, days.
• Days Between Dates. Count days, weeks, months between two dates.
• Business Days Calculator. Count working days, skip weekends and holidays.
• Time Calculator. Add, subtract, or compare hours and minutes.
• Chronological Age Calculator. Age in years;months;days for assessments.
• Week Number. Find the ISO week number for any date.
• Day of the Week. What weekday was any date in history?