Free Date & Time Calculators
Free online tools for date and time: age calculator, days between dates, date calculation, Unix timestamp converter, and ISO week numbers. You no need account.
Free date and time tools wey cover di calculations people dey look for most — exact age, days between two dates, add or subtract time from a date, Unix timestamp conversion, and ISO week numbers. Each tool dey run fully for your browser and you no need account.
Whether you need know how many days remain to reach deadline, which ISO week number one date fall inside, or how to convert Unix timestamp to readable date, dis calculators go give you precise answer instantly.
About each calculator
Age calculator
Di age calculator dey give you your exact age for years, months, and days from any date of birth to any reference date — by default na today. E dey handle leap years correctly: person wey born 29 February get birthday for 28 February for non-leap years for di purpose of age counting. Di result still show total days, weeks, and hours wey don pass since birth.
Exact age for full years, months, and days matter pass as e fit look. Legal thresholds (driving age, retirement age, insurance eligibility), medical references, and contract terms dey often specify age precisely. If you count am by hand across months wey get different lengths and leap years, error fit enter — dis calculator remove dat wahala.
Days between dates calculator
Di days between dates calculator dey count di exact number of calendar days, weeks, months, and business days wey separate any two dates. Business days no include weekends (Saturday and Sunday) but e no count public holidays, wey dey vary by country. Di calculator dey work for both directions — e no require make start date earlier than end date.
Common uses include: calculate notice periods for employment contracts, count days to event or deadline, confirm subscription or billing cycle length, or check how many working days remain for project. For anything wey dey legally binding, calendar days and business days fit give very different numbers — di calculator dey show both.
Date add and subtract calculator
Di date calculator dey add or subtract any combination of days, weeks, months, or years from any starting date. Month arithmetic dey handled correctly: add one month to 31 January go give 28 February (or 29 for leap year), no be 3 March. Dis dey match calendar behaviour and di way contract terms, billing cycles, and legal deadlines dey computed.
Typical uses: calculate deadline 30, 60, or 90 days from today; find di date 6 or 12 months from contract start; project delivery window; or work out due date. Because month and year lengths dey vary, add 1 month no be di same as add 30 days — dis difference important for any date wey anchor legal or financial obligation.
Unix timestamp converter
Unix timestamp na integer wey represent di number of seconds (or milliseconds) wey don pass since di Unix epoch: 00:00:00 UTC on 1 January 1970. Di converter dey accept seconds-precision or milliseconds-precision timestamp and return di equivalent date and time for UTC, local time, and ISO 8601 format. E still dey convert for reverse direction — any date and time back to Unix timestamp.
Unix timestamps dey show for server logs, API responses, database records, JWT tokens, and almost every programming language standard library. JavaScript Date.now() dey return milliseconds; most server-side environments and POSIX functions dey use seconds. Di converter dey detect which one you enter based on di magnitude of di number — values above 10 billion dem dey treat as milliseconds.
ISO week number calculator
Di week number calculator dey return di ISO 8601 week number for any date and show di full year calendar with all 52 or 53 weeks. Under ISO 8601, weeks dey run Monday to Sunday. Week 1 na di week wey contain di first Thursday of di year — so 1 January fit fall for week 52 or 53 of previous year, and 31 December fit fall for week 1 of di next year.
ISO week numbers dey used well well for supply chain management, manufacturing, broadcasting, and project planning. Plenty ERP systems, spreadsheets, and scheduling tools dey reference weeks by number instead of date range. Di calculator still show di Monday and Sunday dates wey bound each week, so you fit convert between week number and specific calendar dates easily.
Which calculator to use
For most date questions, start with di simplest tool wey answer am. "How old I be exactly?" → age calculator. "How many days to my deadline?" → days between dates. "Wetin be di date 90 days from today?" → date add. "Which week number be today?" → week number calculator. "Wetin dis timestamp mean?" → Unix timestamp converter.
Di days between dates and date add calculators overlap small for purpose but dem answer different questions. Days between dey tell you di gap between two known dates. Date add dey tell you which date you reach after given interval. If you know both dates, use days between; if you know di start and interval, use date add.
Frequently asked questions
Wetin be the current ISO week number?
Open the week number calculator and e go show today ISO 8601 week number sharp‑sharp, plus the Monday and Sunday dates wey mark that week. Week 1 na the week wey get the first Thursday for the year, so early January dates fit sometimes fall for week 52 or 53 of the previous year.
How I fit calculate how many days dey between two dates?
Put start date and end date for the days between dates calculator. E go return the exact number of calendar days, weeks, months, and business days wey dey between them. Business days no include weekends, but e no remove public holidays — and holidays dey different for different countries.
Wetin be Unix timestamp?
Unix timestamp na the number of seconds (or milliseconds) wey don pass since 00:00:00 UTC for 1 January 1970, wey dem call the Unix epoch. Na one universal way to represent time as one integer, and dem dey use am for server logs, APIs, databases, and most programming languages.
Wetin be the difference between seconds and milliseconds for Unix timestamp?
Most server‑side systems and POSIX functions dey use seconds. JavaScript `Date.now()` dey return milliseconds — the same timestamp wey dem multiply by 1,000. Seconds‑precision Unix timestamp for mid‑2024 na around 1,700,000,000; the milliseconds version na around 1,700,000,000,000. The Unix timestamp converter go detect which one you enter automatically.
How ISO week numbering take different from normal calendar week?
ISO 8601 weeks dey always run from Monday to Sunday, and week 1 na the week wey get the first Thursday for the year. This mean say 1 January fit dey for week 52 or 53 of the previous year, and 31 December fit dey for week 1 of the next year. Some systems (especially for US) define week 1 as just the week wey get 1 January, and that one fit give different numbers around year boundary.
How I fit calculate my exact age for days?
Enter your date of birth for the age calculator and e go show your age for years, months, days, total weeks, and total days. The calculation dey account for leap years, so e accurate even if your birthday fall for February or near February.
If I add 1 month, e be like add 30 days?
No. If you add one calendar month, e go always land for the same day for the next month — 15 March plus one month na 15 April. If you add 30 days to 15 March, e give 14 April. The difference dey grow when months get different lengths. For contract terms, notice periods, and billing cycles, almost always na calendar months people mean — no be fixed number of days.
Why 31 December dey sometimes fall for week 1 of next year?
Under ISO 8601, if 31 December fall on Monday, Tuesday, or Wednesday, e be part of the first week of the following year — because that week Thursday dey for January. This dey mathematically consistent and e make sure say every week belong clearly to exactly one year, but e fit surprise you the first time you see am.
How many weeks dey inside one year?
Most years get 52 ISO weeks. A year get 53 weeks if 1 January fall for Thursday, or if na leap year and 1 January fall for Wednesday or Thursday. On average, about 71% of years get 52 weeks and 29% get 53.
These calculators dey work for past and future dates?
Yes. All five date and time calculators accept any valid calendar date — past or future. No practical limit dey for range for age, days between, and date add. The Unix timestamp converter cover the full 32‑bit and 64‑bit signed integer range, so e handle dates from 1901 through 2262.
I need account to use these date calculators?
No. Every calculator for this page dey run entirely for your browser. No account, no sign up, no email address needed. Nothing dey sent to server — your inputs stay for your device.
From the blog
How To Calculate Age For Months: Practical Guide For Babies, Records, And PlanningAge for months dey matter pass wetin many people think, especially for babies, forms, and milestones. This guide explain how to calculate age for months well and avoid common mistake.
How To Use Week Number For Project Management — Sprints, Roadmaps, and the Hidden Coordination WahalaWeek number fit look like clean way to plan projects across teams and time zones. E be so — until US engineer and European PM see say dem dey talk different weeks. Na how to use am without the traps be this.
53-Week Years — When E Dey Happen and Why E Dey Cause Wahala for Payroll, Retail, and FinanceMost years get 52 ISO weeks. Some get 53. Dat extra week dey happen for predictable pattern — but e still dey catch payroll systems, retailers, and finance teams off guard every time.
How to Calculate Days Between Dates (And When It Actually Matters)To calculate how many days dey between two dates fit sound simple — but leap years, inclusive counts, and time zones dey confuse people well-well. Here na how e work and when precision really matter.