Date & Time Calculators

Short answer: ToolVaultly’s date and time calculators answer the calendar questions that spreadsheets make awkward: how many days sit between two dates, what date falls ninety days from now, how many business days a deadline really allows, how much time passed between two clock times, and what time a meeting lands in another city. The set also covers chronological age, military time conversion and jet lag planning. Every tool is free, instant, and runs in your browser — no signup, and your dates are never uploaded.

Date maths is easy to get wrong by hand: months have different lengths, weekends hide inside deadlines, and time zones quietly shift meeting times by a day. These calculators handle the edge cases for you — leap years, month boundaries, daylight saving — and show the count plainly so you can plan around it.

Whether you are counting down to a due date, working out an exact age, converting a shift time or scheduling across continents, start with the group that matches your question below. Everything is free and works on any device.

Which date or time calculator do you need?

The date calculator is the generalist: days between dates, adding or subtracting days, and countdowns. If weekends should not count, use the business days calculator instead. For clock times rather than calendar dates, the add time calculator and elapsed time calculator handle hours, minutes and seconds, and the military time converter translates 24-hour times. Planning across zones? The timezone meeting planner finds overlap, and the jet lag calculator builds a recovery plan for the trip itself.

Date Math

Days between dates, deadlines, countdowns and exact ages — the calendar arithmetic most people need.

Date Calculator

Days between dates, add/subtract, live countdown.

Business Days Calculator

Workdays between dates — US holidays, custom weekends, CSV export.

Chronological Age Calculator

Exact age in years, months & days — leap-year correct.

Time Math

Adding and subtracting clock times, measuring durations, and converting between 12-hour and 24-hour time.

Add Time Calculator

Add, subtract, multiply & divide times with step-by-step working.

Elapsed Time Calculator

Duration between two times — or work back to start/end.

Military Time Converter

Standard ↔ military time, full 24-hour chart, spoken pronunciation.

Time Zones & Travel

Meeting times that work across cities, and a recovery plan for your body clock when you fly between them.

Timezone Meeting Planner

Meeting times across time zones — overlap grid, best slot, share link.

Jet Lag Calculator

A personal jet-lag recovery plan for your route & sleep schedule.

Frequently asked questions

How do I count the days between two dates?

Open the date calculator, enter the start and end dates, and it returns the exact number of days — plus weeks and a breakdown — counting leap years correctly. Tick the option to include the end date if your deadline counts both ends.

What is the difference between the date calculator and the business days calculator?

The date calculator counts every calendar day. The business days calculator skips weekends, which is what most work deadlines, delivery promises and processing times actually mean.

Do these tools handle leap years and daylight saving?

Yes. Day counts use the real calendar, including February 29th, and the time-zone tools use current daylight-saving rules for the cities involved.

Are the date and time calculators free?

Yes — free, no signup, no limits. They run entirely in your browser, so the dates you enter are never sent anywhere.

Can I work out someone’s exact age?

Yes — the chronological age calculator gives age in years, months and days from a birth date, which is the format schools, sports leagues and forms usually want.

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