Cable Length Calculator

Step-by-Step Guide

1. 1Enter the measured distance: Type the point-to-point distance between the cable origin and destination, measured with a tape measure or laser meter, and choose meters or feet. This is your base distance before any allowances are added.
2. 2Select the cable type: Choose electrical power, Ethernet (Cat5e/6), fiber optic, or coaxial. This sets the recommended slack percentage the calculator suggests and determines which cable-specific warnings appear in your results.
3. 3Choose the installation method: Select straight run, conduit, wall routing, underground, or overhead. Each method applies a different multiplier to your subtotal — underground adds the most length (1.15×) for settling and future access, straight run adds none (1.0×).
4. 4Set slack percentage and bend count: Adjust the slack slider or click 'Use Recommended' to auto-fill the standard percentage for your cable type. Enter the number of 90-degree bends or turns in the route and the allowance per bend, typically 0.3–0.5 meters.
5. 5Read the total length and breakdown: The calculator instantly shows total cable length in meters and feet, plus a line-by-line breakdown of base distance, slack added, bend allowance, and the installation factor applied. Review any recommendations flagged for your specific inputs.
6. 6Save, export, or apply a preset: Save the calculation to your local history for later reference, export a text or CSV report for purchasing, or start from one of six built-in presets — home electrical run, office network cable, data center fiber, and more — then adjust from there.

What This Tool Provides

• ✓Real-time calculation as you type or adjust the slider
• ✓Results in both meters and feet
• ✓Four cable types: electrical, Ethernet, fiber, coaxial
• ✓Five installation methods with accurate multipliers
• ✓One-click recommended slack per cable type
• ✓Smart warnings for excessive bends and long runs
• ✓Six built-in scenario presets to start from
• ✓Calculation history (last 20 entries) saved locally
• ✓Export results as text report or CSV
• ✓Copy result to clipboard
• ✓100% browser-based — no data sent to a server
• ✓No registration required

Pro Tips

• 💡Measure the actual routed path, not the straight-line distance between two points. If the cable has to rise through a ceiling, cross a hallway, and drop down a wall, add each segment separately rather than measuring point-to-point through the floor plan — the calculator's bend and installation factors assume you've already captured the real path length.
• 💡Use the 'Use Recommended' slack button as a starting point, then adjust upward if your installation has unusual access constraints. Fiber optic splice trays, for example, often need closer to 20% rather than the default 15% if the splice enclosure is mounted far from the equipment rack.
• 💡Count every 90-degree equivalent bend, not just visually obvious corners. A cable that curves gradually around a wide radius still consumes extra length even without a sharp corner — estimate the equivalent number of 90-degree bends for gradual curves.
• 💡For underground runs, don't skimp on slack just because the trench is freshly dug. Soil settles over months, and a taut buried cable with no service loop can be damaged or pulled tight at termination points — the 15–20% recommendation exists specifically for this reason.
• 💡When ordering cable, round the calculator's total up to the next standard spool or box size rather than ordering the exact calculated length. Cable is typically sold in 15m, 30m, 50m, 100m, or 305m (1000ft) increments, and cutting waste plus measurement error easily consumes a meter or two of margin.
• 💡Save each calculation to history before starting a new one if you're estimating multiple runs for the same project. The history panel lets you review distance, cable type, slack, and bend count for every saved run when compiling a full material list.

Common Mistakes to Avoid

• ✕Don't enter the straight-line floor-plan distance as your base distance when the actual cable route is longer. A cable running from a first-floor panel to a second-floor outlet travels up through a wall cavity and across a ceiling void — the vertical rise alone can add several meters that a flat floor-plan measurement misses entirely.
• ✕Don't leave bend allowance at zero for a conduit, wall, or underground installation. These installation types imply the cable isn't running in a straight line, and the calculator itself warns when bends are set to 0 with a non-straight installation type selected — skipping this understates your total by a meaningful margin on runs with multiple turns.
• ✕Don't ignore the calculator's warning about Ethernet runs approaching or exceeding 90 meters. This isn't a soft guideline — beyond 90 meters of fixed cable, TIA/EIA-568 signal timing budgets are exceeded and the link becomes unreliable regardless of cable quality; the fix is a switch or fiber, not a longer copper run.
• ✕Don't apply the same slack percentage to every cable type out of habit. Fiber optic cable's splice tray requirements genuinely need more slack (15–20%) than a simple electrical termination (10%), and using a flat 10% across all cable types under-orders fiber and over-orders electrical cable.
• ✕Don't order the exact calculated total with zero buffer. The calculator's output is a precise estimate based on your inputs, but on-site conditions — an unexpected obstruction, a miscounted bend, a cutting error — routinely consume a meter or more. Round up to the next practical spool length rather than ordering to the decimal.