Tech
Everyday tech numbers: screen sizes, storage and data usage, download times, battery life and resolution.
67 free tools in this category. See every tool on Lelifi.
- Amp-Hour CalculatorTurn current in amps and run time in hours into battery capacity in amp-hours, t
- Amps to kVA CalculatorConvert amps and volts to kVA for single phase or three phase power. See kW, kVA
- Audio File Size Calculator: WAV, MP3 and Storage TimeCalculate audio file size for uncompressed WAV or compressed MP3 from sample rat
- Bandwidth CalculatorConvert Mbps to MB/s, add up what each person and device needs at once, and see
- Battery Charge Time CalculatorEnter battery mAh, voltage and charger watts to see how long a full charge takes
- Battery Life CalculatorTurn mAh and current draw into real runtime, then see how much capacity 500 char
- Bits to Bytes ConverterConvert bits to bytes and every size up to terabytes. See kB vs KiB, MB vs MiB,
- CFM CalculatorFind CFM from room volume and air changes, duct size and velocity, or a sensible
- CapacitanceEnter any two of charge, voltage, capacitance or stored energy and get the other
- Capacitor CalculatorEnter capacitance and voltage to get stored charge in coulombs and energy in jou
- Current CalculatorCurrent in amps from volts and ohms, watts and volts, or watts and ohms, plus mi
- Data Transfer CalculatorEnter the gigabytes and the route to see a realistic transfer time, the delivere
- Data Usage CalculatorEstimate your monthly data usage. Enter hours of video, music, gaming, calls, an
- Download Time CalculatorSee how long a download takes from file size and speed. Handles the megabits to
- Downtime Cost CalculatorWork out what an hour of downtime costs: lost gross profit, idle labor and overh
- Electric Charge CalculatorConvert current and time into charge in coulombs, amp-hours and electrons, plus
- Electric Potential CalculatorFind the electric potential at a distance from a point charge with V = kQ/r. A 1
- Electricity CalculatorDivide your bill total by your kWh to get the price each kilowatt hour costs, th
- Electricity Cost CalculatorTurn watts and hours into a real bill. See what any appliance costs per hour, mo
- How Many Hours of Video Per GBSee how many hours of video fit on any card or drive. At 8 Mbps 1080p uses 3.6 G
- How Many Photos Can I Store?Work out how many photos and videos fit on your phone, SD card or cloud plan. En
- How Many Songs Fit CalculatorHow many songs fit calculator: pick your storage size and audio bitrate to see t
- How Much Data Does Gaming Use Per Hour?Online gaming uses about 100 MB an hour, downloads run 50 to 150 GB, and cloud g
- IP Subnet CalculatorWork out the subnet for any IPv4 address and prefix: network, broadcast, mask, w
- Internet Speed CalculatorWork out how long a download takes: enter the file size and your connection spee
- KV to RPM CalculatorThis KV to RPM calculator turns KV and pack voltage into no-load RPM, loaded RPM
- LED Resistor CalculatorSize a current limiting resistor for any LED: enter supply volts, forward volts
- MB to GB ConverterConvert megabytes to gigabytes instantly. Enter any amount in MB and see the GB
- Mbps ConverterConvert Mbps to MB/s, Gbps and Kbps, then see how long a 1 GB file takes in prac
- Mbps to Gbps ConverterConvert Mbps to Gbps by dividing by 1,000. See the same speed in MB/s, how long
- Netflix Data Usage CalculatorCalculate how much data Netflix uses per hour and per month across SD, HD, and 4
- Ohm's LawWhat Ohm's law means, where the V = I x R triangle comes from, when the rule hol
- Ohm's Law CalculatorEnter any two of voltage, current, resistance or power and get the other two, wi
- Parallel Resistance CalculatorParallel resistance calculator: combine up to five resistors into one equivalent
- Peak Voltage CalculatorConvert peak voltage from RMS or peak to peak for sine, triangle and square wave
- Peak to Peak Voltage CalculatorConvert peak to peak voltage from RMS or peak for sine, triangle and square wave
- Phone Charging Time CalculatorFree phone charging time calculator: enter your battery size, current charge and
- Phone Screen Size CalculatorTurn a phone's diagonal and resolution into real width, height, area and pixel d
- Pixel RulerTurn screen pixels into inches and centimeters. Calibrate with a bank card, then
- Pixels Per Inch CalculatorEnter resolution and screen size to get pixels per inch, dot pitch and the PPI y
- Projector CalculatorEnter screen size, throw ratio and room light to get image width, throw distance
- Resistance CalculatorFind resistance three ways: from voltage and current with R = V/I, from series r
- Screen Resolution CalculatorFree screen resolution calculator: enter any resolution and screen size to get p
- Screen Size CalculatorMeasure a screen's width and height and get the diagonal in inches, area, aspect
- Screen Size Comparison CalculatorCompare two screen sizes by real width, height and area, see how 16:9 and 21:9 d
- Series Resistance CalculatorAdd resistors in series to get the total resistance, then with an optional suppl
- Storage ConverterConvert between bytes, KB, MB, GB, TB and PB in both decimal (1000) and binary (
- Streaming Bitrate CalculatorTwitch and YouTube bitrate guide: recommended kbps for 720p to 4K at 30 and 60 f
- Streaming Data Usage CalculatorWork out how many GB your streaming uses each month: video, music, calls and gam
- TV Size and Viewing Distance CalculatorEnter your screen size and resolution to get the recommended viewing distance in
- Upload Time CalculatorFind out how long a file will take to upload: enter the file size and your uploa
- VA to kVA CalculatorDivide volt-amps by 1,000 to get kVA, then read the amps, kW and kvar behind the
- VA to kW CalculatorConvert volt-amps to kilowatts with a power factor you choose: kW = VA x PF / 10
- Video File Size CalculatorEnter a clip length, video and audio bitrate to get the file size in MB and GB,
- Voltage CalculatorCalculate voltage three ways: V = I x R, V = P / I and the square root of P x R,
- Voltage Divider CalculatorWork out the output of a two resistor voltage divider, with and without a load,
- Voltage Drop CalculatorFind the voltage drop on a copper or aluminum run in single or three phase circu
- Wh to mAh CalculatorTurn watt-hours into milliamp-hours at any voltage. 74 Wh at 3.7 V is 20,000 mAh
- Wire Ampacity CalculatorFind wire ampacity for 14 AWG to 4/0 copper or aluminum at 60, 75 or 90 C, then
- Wire Size CalculatorPick copper wire size from load amps and run length: NEC ampacity, voltage drop
- kVA to VA CalculatorConvert kVA to volt-amps and back, see the amps behind any kVA at your voltage,
- kVA to kW CalculatorConvert kVA to kW with the power factor, work back from kW to kVA, and see the a
- kW to kVA CalculatorDivide kilowatts by the power factor to get kVA: 100 kW at 0.8 pf is 125 kVA, pl
- kW to kWh CalculatorConvert kW to kWh with hours of use, plus the monthly and yearly cost at 18.16 c
- kWh to kW CalculatorConvert kilowatt-hours to average kilowatts over any period, and kW back to kWh.
- mAh to Hours CalculatorConvert a battery's mAh rating and your device's draw into runtime in hours, plu
- mAh to Wh CalculatorConvert milliamp hours to watt hours at any voltage, see why voltage changes the
Tech numbers get confusing because the same letters mean different things. Internet speed is sold in megabits while file size is shown in megabytes, and a drive sold as 1 TB shows up smaller once an operating system counts in the other base. These tools untangle the units so you can plan storage, data and battery life without surprises.
Speed, size and the factor of 8
There are 8 bits in a byte, so a 100 Mbps connection delivers 12.5 MB/s, not 100. That one division explains most cases of a connection that feels slow. A 5 GB file at 100 Mbps takes about 400 seconds, or 6 minutes 40 seconds, once you allow for a little overhead. On a 25 Mbps plan the same file takes over 26 minutes.
- Storage: a 1 TB drive is 1,000 GB in decimal, but an operating system that counts in 1,024 units reports about 931 GB.
- Photos and songs: a 64 GB card holds roughly 6,700 photos at 9 MB each, and song counts depend on the audio bitrate you pick.
- Battery: a 5,000 mAh phone battery divided by a 500 mA draw runs about 10 hours, and watt-hours matter for airline and power-bank limits.
- Streaming: high-definition video can use 3 GB an hour, so a 50 GB data cap covers about 16 hours.
When a number looks wrong, check which unit it is in before assuming the hardware is broken.