Category
Energy & Workshop Math
Everyday electrical and workshop arithmetic: watts, amps, volts and watt-hours with the circuit assumptions spelled out, plus airflow and runtime estimates for real spaces and equipment.
Calculators in this category
AC Size Calculator
Estimate room air-conditioner capacity from floor area and conditions.
Open calculator →Air Changes Per Hour Calculator
Compute ACH from room volume and airflow, in cubic metres per hour or CFM.
Open calculator →Amps to Watts Calculator
Convert load current in amps to real power in watts for DC, AC single-phase or balanced three-phase circuits.
Open calculator →BTU Calculator
Estimate room cooling BTU per hour from area and simple adjustments.
Open calculator →Battery Runtime Calculator
Estimate how long a battery will run a load, with explicit usable-energy and efficiency assumptions.
Open calculator →CFM Calculator
Convert cooling capacity to airflow, or size room airflow from volume and ACH.
Open calculator →LED Resistor Calculator
Calculate the series resistor for one LED string from supply and forward voltage.
Open calculator →Voltage Drop Calculator
Estimate conductor voltage drop from length, current, supplied resistance and power factor.
Open calculator →Watts to Amps Calculator
Convert real power in watts to load current for DC, AC single-phase or balanced three-phase circuits.
Open calculator →Wire Size Calculator – Voltage-Drop Comparison
Compare listed reference gauges against a chosen voltage-drop limit.
Open calculator →Choosing between these tools
Choose the tool for the quantity you need, then use its matching measurement mode. Check the product basis before turning area or volume into a purchase order.
Check electrical arithmetic
Start with the correct circuit type, voltage and power factor. Current and voltage-drop comparisons do not approve a breaker, conductor ampacity or installation.
Watts to Amps Calculator · Amps to Watts Calculator · Voltage Drop Calculator · Wire Size Calculator – Voltage-Drop Comparison
Compare room cooling and airflow
The AC chart estimates room cooling capacity. BTU exposes an area rule. CFM and ACH convert flow and room volume; they do not prescribe a safe ventilation target.
AC Size Calculator · BTU Calculator · CFM Calculator · Air Changes Per Hour Calculator
Estimate small DC projects
Budget usable energy and conversion losses for runtime. For LEDs, use datasheet forward voltage and target current; high-power LEDs need suitable drivers.
Battery Runtime Calculator · LED Resistor Calculator · Watts to Amps Calculator