Time Converter
Convert between seconds, minutes, hours, days, weeks, months, years and more time units
Unit Converter
Support fast conversion of various units including length, area, volume, weight, temperature, etc.
Common Units
Common Unit Conversions
Quick reference for frequently used unit conversions
Length
| From | To | Formula | Example |
|---|---|---|---|
| Inches (in) | Centimeters (cm) | in × 2.54 | 1 in = 2.54 cm |
| Feet (ft) | Meters (m) | ft × 0.3048 | 1 ft = 0.3048 m |
| Miles (mi) | Kilometers (km) | mi × 1.609 | 1 mi = 1.609 km |
| Meters (m) | Feet (ft) | m × 3.281 | 1 m = 3.281 ft |
| Kilometers (km) | Miles (mi) | km × 0.621 | 1 km = 0.621 mi |
Weight / Mass
| From | To | Formula | Example |
|---|---|---|---|
| Ounces (oz) | Grams (g) | oz × 28.35 | 1 oz = 28.35 g |
| Pounds (lb) | Kilograms (kg) | lb × 0.454 | 1 lb = 0.454 kg |
| Kilograms (kg) | Pounds (lb) | kg × 2.205 | 1 kg = 2.205 lb |
| Tons (t) | Tonnes (t) | t × 0.907 | 1 t = 0.907 tonnes |
Volume
| From | To | Formula | Example |
|---|---|---|---|
| Fl oz (US) | Milliliters (ml) | fl oz × 29.574 | 1 fl oz = 29.574 ml |
| Cups (US) | Milliliters (ml) | cup × 236.588 | 1 cup = 236.588 ml |
| Pints (US) | Liters (L) | pt × 0.473 | 1 pt = 0.473 L |
| Gallons (US) | Liters (L) | gal × 3.785 | 1 gal = 3.785 L |
| Liters (L) | Gallons (US) | L × 0.264 | 1 L = 0.264 gal |
Temperature
| From | To | Formula | Example |
|---|---|---|---|
| Celsius (°C) | Fahrenheit (°F) | (°C × 9/5) + 32 | 0°C = 32°F |
| Fahrenheit (°F) | Celsius (°C) | (°F - 32) × 5/9 | 32°F = 0°C |
| Celsius (°C) | Kelvin (K) | °C + 273.15 | 0°C = 273.15 K |
| Kelvin (K) | Celsius (°C) | K - 273.15 | 273.15 K = 0°C |
Area
| From | To | Formula | Example |
|---|---|---|---|
| Sq feet (ft²) | Sq meters (m²) | ft² × 0.0929 | 1 ft² = 0.0929 m² |
| Sq meters (m²) | Sq feet (ft²) | m² × 10.764 | 1 m² = 10.764 ft² |
| Acres | Hectares (ha) | acre × 0.405 | 1 acre = 0.405 ha |
| Hectares (ha) | Acres | ha × 2.471 | 1 ha = 2.471 acres |
Speed
| From | To | Formula | Example |
|---|---|---|---|
| MPH | KM/H | mph × 1.609 | 1 mph = 1.609 km/h |
| KM/H | MPH | km/h × 0.621 | 1 km/h = 0.621 mph |
| Knots | MPH | knots × 1.151 | 1 knot = 1.151 mph |
| M/S | KM/H | m/s × 3.6 | 1 m/s = 3.6 km/h |
Note: These are commonly used conversions with approximate values rounded for practical use. For precise conversions, use the calculator tool above.
Unit Conversion Reference Table
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What is Time Conversion?
Time conversion translates a duration from one unit to another — hours to seconds, days to weeks, milliseconds to minutes. It is used in scheduling, computing, science, and project planning.
Time units are unusual because they are not all powers of ten. The second is the SI base unit, but above it the system uses 60 (seconds per minute, minutes per hour) and 24 (hours per day) — vestiges of ancient Babylonian and Egyptian systems. Below the second, units are decimal: millisecond (10⁻³), microsecond (10⁻⁶), nanosecond (10⁻⁹).
Larger units like weeks, months, and years add more irregularity: a week is exactly 7 days, but months range from 28 to 31 days, and a year is about 365.25 days (hence leap years). This is why month and year conversions are always approximate.
How to Convert Time Units
Time units have conversion rates relative to a base unit (the second):
result = value × (fromUnit rate) ÷ (toUnit rate)
Example — convert 2.5 hours to seconds:
2.5 h = 2.5 × 3600 ÷ 1 = 9,000 s
Key tip: Memorize the key anchors: 1 minute = 60 s, 1 hour = 3,600 s, 1 day = 86,400 s. Everything else can be derived from these.
Common Time Conversions
| From | To | Multiply by |
|---|---|---|
| Minute | Second | 60 |
| Hour | Second | 3,600 |
| Day | Hour | 24 |
| Week | Day | 7 |
| Year | Day | 365.25 |
Frequently Asked Questions
How many seconds are in an hour?
There are 3,600 seconds in one hour (60 minutes × 60 seconds). One day has 86,400 seconds. To convert hours to seconds, multiply by 3,600. To convert seconds to hours, divide by 3,600.
How do I convert hours to days?
Divide hours by 24 to get days. For example, 72 hours = 72 ÷ 24 = 3 days. To convert days to hours, multiply by 24. A work week of 40 hours is about 1.67 days. Note that calendar months vary (28–31 days), so month conversions are approximate.
How many minutes are in a year?
A common year has 365 days × 24 hours × 60 minutes = 525,600 minutes. A leap year (366 days) has 527,040 minutes. This is why the musical Rent asks “how do you measure a year? 525,600 minutes.”
How many milliseconds are in a second?
There are 1,000 milliseconds (ms) in one second, and 1,000,000 microseconds (μs). A nanosecond is one-billionth of a second (10⁻⁹ s). Computers operate on nanosecond timescales — a 3 GHz processor completes one cycle roughly every 0.33 nanoseconds.
Why are months not exact multiples of days?
Months are based on the Moon’s orbit and range from 28 to 31 days, so they cannot be converted precisely using a fixed factor. For conversions, we often use an average month of 30.44 days (365.25 ÷ 12), but this is always approximate. Scientific work uses days, seconds, or years instead.