Business & IT Date Calculator

CyprNet DeltaCalc is a precision date and time calculator built for answers you can understand, verify, and explain. Calculate differences between dates, work with BCE/CE historical dates, count business days and holidays, create countdowns, convert Unix timestamps, calculate ISO dates, and round timesheets. DeltaCalc is a calculator—not a calendar, reminder, or task manager. Your calculations stay on your device. Free calculators Between Two Dates/Times Calculate calendar years, months, and days plus total weeks, days, hours, minutes, and seconds. Historical BCE/CE Dates Calculate date differences and add or subtract calendar offsets across BCE and CE dates. Add / Subtract Date & Time Add or subtract years, months, weeks, days, hours, or minutes from a date and time. Countdown Create live in-app countdowns for retirement, events, milestones, vacations, launches, birthdays, and more. Business Days Calculate working days using Saturday–Sunday or Friday–Saturday weekends, with built-in holiday calendars for: United States Federal holidays England & Wales Canada Unix Epoch Converter Convert Unix epoch timestamps to local dates and times. TLS Certificate Dates Calculate certificate issue, renewal, and expiration schedules using TLS certificate timing rules. ISO Date See ISO week, ISO year, quarter, day-of-year, and related calendar information. Timesheet Rounding Round clock-in and clock-out times using 5, 6, 10, 15, or 30-minute increments with nearest, up, or down rules. Pro calculators A one-time Pro unlock adds advanced tools: Lease Term Notice Window Proration Installment Dates TTL & Cache Expiration SLA Availability / Downtime Maintenance Windows Log Timestamp Conversion Shifts & Overtime Advanced Timesheet Rounding Time Accounting Age & Tenure Recurring Events Sprint & Release Dates Fiscal Calendars, including 4-4-5 Pro history and saved work Pro also adds: Up to 50 persisted history entries Up to 20 named reusable scenarios Favorite calculators CSV export JSON export XML export Free users can still keep the five most recent calculations during the current session and share individual results. Designed for privacy DeltaCalc performs calculations locally on your Android device. No ads No subscriptions No analytics SDKs No accounts No cloud calculation service No calendar access No GPS tracking No background alarms No notification spam One-time Pro unlock Unlock all Pro features with a $0.99 purchase. No recurring fee. Restore your purchase automatically with the same Google Play account, or use Settings → Restore purchases. Useful for DeltaCalc is designed for anyone who regularly works with dates and times, including: IT and DevOps Network administrators Project managers Consultants Legal and contract workflows Payroll and workforce calculations Business operations Students and researchers Historical date calculations Everyday planning Whether you need to know how many business days remain before a deadline, when a TLS certificate should be renewed, how long until retirement, how old a historical date is, or exactly how much downtime a service-level target allows, DeltaCalc gives you the math without turning the calculation into another calendar or subscription service. CyprNet DeltaCalc Precision date and time math—local, private, and explainable. What's new — Version 1.0.7 DeltaCalc 1.0.7 greatly expands the calculator set. New: Countdown, including retirement and event countdowns BCE/CE historical date calculations Business-day calculations with US, England & Wales, and Canada holiday calendars TLS certificate date calculations ISO date information Timesheet rounding Recurring events Sprint and release dates Fiscal calendars Time accounting Advanced rounding Also improved: Pro history now survives restart Up to 20 named Pro scenarios Pro favorites persist Still one-time Pro. No ads. No subscriptions. No calendar sync.