Practical calculation tools for Airfield Ground Lighting design, electrical systems, equipment selection, and field engineering — organised by category and technically validated before publishing.
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Airfield lighting runs on constant-current series circuits: a constant current regulator (CCR) pushes the same current through every fixture, and the voltage it must deliver depends on the total resistance and impedance of the loop. The calculators above follow that logic, so you can size a CCR, check a cable run or plan a new circuit without a spreadsheet.
Everything starts with V = I × R. In a series circuit the current is fixed by the CCR brightness step, so the voltage the CCR must supply is that current multiplied by the total circuit resistance. Power lost as heat in the cable is P = I² × R. Use the Ohm's Law Calculator to solve any one of V, I, R or P from two known values; the Series Circuit Impedance, Primary Cable Resistance and Circuit Voltage calculators apply it directly to airfield circuits.
The Series Circuit Load calculator totals fixture wattage, isolating transformer losses and cable I²R loss, then checks the result against the CCR. Use AGL Circuit Length Estimator to estimate primary cable from fixture count and spacing, and Circuit Power Factor when the load mixes fixture types.
Voltage drop in the primary cable is the circuit current times the cable resistance over its length. A longer run or a smaller conductor raises it, and the CCR has to make up the difference. The Cable Voltage Drop calculator handles runway lighting voltage drop, taxiway lighting voltage drop and any other primary series run, and shows the maximum length for a chosen drop limit. For the short lead between an isolating transformer and its fixture, use Secondary Cable Voltage Drop.
Cable size is chosen so that voltage drop, I²R loss and the cable's voltage rating all stay within limits for the length of the circuit. Use the AGL Cable Size Selection Calculator to pick the smallest conductor that meets your limits, or compare conductors in the Cable Voltage Drop, Primary Cable Resistance and Cable Power Loss calculators.
An airport lighting load calculation, airport lighting power calculation and airport lighting current calculation all start from the same circuit data. Circuit load is the sum of all fixture watts, plus isolating transformer losses and cable loss, expressed in kW and kVA. Current is set by the CCR step you run the circuit on, so a current calculation is really a check that each step stays within the allowable range; the CCR Step Current / Brightness Reference lists those steps. To see how many more fixtures an existing circuit can take, use AGL Spare Capacity Calculator.
Runway lighting load calculation, runway lighting power calculation, taxiway lighting load calculation and taxiway lighting power calculation all use the same method as above; only the fixture counts and cable lengths differ.
The Runway & Taxiway Lighting Load / Power Calculator gives kW and kVA by circuit for the runway, the taxiway and the whole system. The Series Circuit Load calculator works as an airport lighting load calculator, runway lighting load calculator, runway lighting power calculator, taxiway lighting load calculator and taxiway lighting power calculator. Enter the fixture count, transformer losses and cable length for the circuit in question.
CCR size is the output voltage times the circuit current, divided by 1,000 to give kVA. The CCR Capacity calculator adds an expansion allowance and a maximum loading limit, then picks the smallest standard CCR size that covers the load. CCR Selection & Loading picks the smallest standard CCR and checks loading at every brightness step. Transformer VA Selection does the equivalent for isolating transformers.
Energy use is power times operating hours, and cost is energy times your tariff. The Cable Power Loss calculator already reports yearly cable-loss energy. The Series Circuit Energy & Operating Cost calculator covers CCR load, operating hours and tariff for the full yearly energy and cost.
Light spacing depends on the lighting type and the standard you design to (ICAO Annex 14 or FAA AC 150/5340-30). Try Approach Lighting Quantity Tool for approach light spacing and station counts, Threshold & Runway-End Lights for runway threshold light spacing, and Stop Bar & Holding Position Lights for stop bar light spacing. Edge Light Spacing covers runway edge lights.
AGL design calculations turn a lighting layout into circuit data: number of lights, circuit load, cable resistance, voltage drop and CCR size. Do them in order, and recheck them when the layout changes. The calculators above cover each step.
AGL engineering calculations cover the electrical sizing of the series circuit and the layout of the lights. Keep a record of the inputs, the method and the results, so the design can be reviewed and later changes can be checked.
An airfield ground lighting calculation starts with the lights on a circuit and ends with the CCR rating. Typical steps are fixture and transformer load, cable resistance, total voltage, kVA and a margin for growth.
An airfield lighting calculation sizes the electrical system that feeds the lights: load, current, voltage, cable and regulator. It is separate from the photometric calculation, which checks the light output.
An airport lighting calculation covers the electrical and layout figures behind an AGL design. The sections below list the main ones, and the calculators above carry them out.
A runway lighting calculation finds the number of lights, the circuit split, the load on each circuit and the size of each CCR. Runway circuits are usually separated so one fault does not remove all the lights.
A taxiway lighting calculation sizes the circuits for edge and centreline lights, which are often spread over long and branching routes. Cable length and voltage drop usually need most attention.
An approach lighting calculation sizes the circuits for the approach lights, which can be long and carry high-wattage lamps. Load and cable resistance determine the CCR size and the circuit split.
A runway edge lights calculation counts the lights along both edges and finds the load they place on the circuit, including the isolating transformers and cable.
A runway centreline lights calculation counts the lights along the centreline and finds their load on the circuit. The centreline lights are normally on their own circuit.
A threshold lights calculation counts the threshold and wing bar lights and finds their load. They are often supplied from a separate circuit from the edge lights.
An airfield lighting load calculation adds the fixture wattages, transformer losses and cable loss to give the circuit load in kW and kVA. Compare it with the CCR rating and leave spare capacity. The Series Circuit Load calculator does this.
An AGL power calculation finds the real power and the apparent power drawn by a circuit. The cable loss is I² × R, and the CCR also has its own losses and power factor, which the manufacturer gives.
An AGL series circuit calculation finds the total resistance or impedance the CCR must drive at full current, then the voltage and kVA needed. The same current flows through every light.
A constant current regulator calculation finds the output voltage and kVA needed for a circuit, then selects the next standard CCR size with margin. See CCR Capacity.
An airfield lighting isolation transformer calculation chooses the transformer rating for the lamp wattage, and adds the transformer losses and magnetising effect to the circuit load. Use the manufacturer's data for the figures.
An airfield lighting control system calculation sizes the control hardware: the number of inputs and outputs, the circuits to be monitored and the power for the control equipment. It follows the circuit schedule.
An ALCMS calculation sizes the control and monitoring system: the number of circuits, monitoring points, panels and communication links. It follows the circuit schedule and the control philosophy.
An airfield lighting cable calculation picks a conductor size and checks resistance, voltage drop, I² × R loss and ratings over the full circuit length. The Cable Voltage Drop calculator supports it.
AGL cable voltage drop is the voltage lost in the cable at the circuit current, I × R. In a series circuit it adds to the voltage the CCR must supply, so long cables raise the CCR size. Use the Cable Voltage Drop calculator.
An AGL voltage drop calculation multiplies the circuit current by the total cable resistance, using the conductor resistance per length and the full length. Check the result against the CCR output and the cable rating. See Cable Voltage Drop.
Runway lights spacing is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves.
Runway lighting spacing is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves.
Runway centreline light spacing is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves. The centreline lights are checked against the runway length and any changes in spacing along it.
Runway centreline lights spacing is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves.
Taxiway lighting spacing is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves. Spacing is often closer on curves and at intersections.
Airfield lighting spacing is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves.
Airfield ground lighting spacing is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves.
Airport lighting spacing is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves.
Runway light spacing calculation is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves. Divide the length by the spacing, then add the end light.
Taxiway light spacing calculation is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves.
Airfield lighting spacing calculation is set by the applicable standard and the approved design, and it depends on the light type and the layout. The count of lights follows from the length and the spacing, with allowance for ends, intersections and curves.
AGL series circuit spacing is how the lights and transformers are placed along a circuit. Placement sets the cable length, so it affects the circuit resistance and voltage drop.
Constant current regulator spacing is where the CCRs are placed in relation to the circuits they feed. A CCR close to its circuit reduces the cable length and the voltage drop.
Airfield lighting isolation transformer spacing follows the light spacing, as there is normally one transformer for each light. Place it close to the fixture so the secondary leads stay short.
Airfield lighting cable spacing covers the separation between cables, ducts and other services. It affects heating, installation and fault risk, and comes from the cable data and the design.
Airfield lighting control system spacing is how control and monitoring equipment is spread over the airfield. It follows the circuit layout and the communication limits of the equipment.
ALCMS spacing is where the ALCMS field units, panels and network nodes are placed. It follows the circuit layout, the cable routes and the communication limits.
Add the wattage of every fixture on the circuit, then add the losses in the isolating transformers and the I²R loss in the primary cable. The total, in kW and kVA, is the circuit load. Compare it with the CCR rating, leaving spare capacity for expansion. The Series Circuit Load calculator does this.
Work out the voltage the CCR must supply at full current (current times total circuit resistance or impedance), multiply by that current to get kVA, add an allowance for growth, and choose the next standard size up. See CCR Capacity.
Pick a conductor whose resistance keeps voltage drop and I²R loss acceptable over the full circuit length, and whose voltage and current ratings suit the circuit. Larger conductors lower the loss but cost more, so designers compare options. The Cable Voltage Drop and Primary Cable Resistance calculators support that comparison.
Multiply the circuit current by the resistance of the cable section (resistance per unit length times length, corrected for temperature). Sum the sections for the whole run. The Cable Voltage Drop calculator works section by section.
Multiply the circuit current by the total cable resistance, which is the conductor resistance per length times the full circuit length. In a series circuit the current is set by the CCR brightness step, and the voltage drop adds to the voltage the CCR must supply. Check the result against the CCR output and the cable rating with the Cable Voltage Drop calculator.
Take the required spacing for the light type from the applicable standard and the approved design, then divide the length to be lit by that spacing and add the end light. Adjust for intersections, curves and changes in spacing, and round to whole lights. The light count then feeds the load and CCR calculations.
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