| Path length | Width | Layout | Spacing used | Total lights | Notes |
|---|---|---|---|---|---|
| 20 m | 1.2 m | Both sides (staggered) | 2.6 m | 8 | Functional preset with 0.6 m mount height. |
| 30 m | 1.5 m | Both sides (aligned) | 3.0 m | 22 | Manual spacing; symmetric look on straight paths. |
| 12 m | 1.0 m | Centerline | 2.2 m | 6 | Good for narrow paths or minimalist edging. |
- Beam spread diameter (approx): D = 2 × h × tan(θ/2) where h is mount height and θ is beam angle.
- Recommended spacing: S = D × coverage Coverage (0.40–0.95) sets overlap between light pools.
- Line count by spacing: N = ceil((L − 2×offset)/S) + 1 If L − 2×offset ≤ 0, then N = 1.
- Minimum lights by brightness (approx): Nlux = ceil((Lux × Area) / (Lumens × UF × MF)) UF is utilization factor; MF is maintenance factor.
- Final count: Nfinal = max(Nspacing, Nlux) Uses the more conservative requirement.
- Measure path length along the walking line.
- Measure average path width for lux estimates.
- Choose a layout: one side, both sides, or centerline.
- Pick Auto spacing for guidance, or Manual for fixed plans.
- Set mount height and beam angle from your fixture specs.
- Adjust utilization and maintenance for real-world conditions.
- Review totals, spacing, and transformer headroom in results.
- Export CSV or PDF to save and share the plan.
Spacing targets and visual rhythm
Most garden paths look balanced when fixtures repeat at steady intervals. A practical starting range for common low-voltage path lights is 2.0–3.5 meters (6.5–11.5 feet) between consecutive fixtures. Closer spacing reduces dark gaps and improves step visibility, while wider spacing emphasizes landscape accents. This calculator estimates beam spread from height and beam angle, then applies a coverage factor to maintain overlap.
How layout changes the required count
Layout affects both symmetry and perceived brightness. One-side layouts minimize hardware but can leave the opposite edge dim on wider paths. Both sides aligned creates a formal look and usually doubles the count compared with one side. Both sides staggered alternates fixtures, smoothing brightness transitions along the walking line. Centerline placement can work on narrow paths but needs strong glare control.
Using lux and lumen inputs responsibly
This tool estimates a minimum count using a simple lux approach: target lux multiplied by path area gives required lumens on the walking plane. Because not all rated lumens reach the ground, utilization and maintenance factors reduce effective output. For many residential paths, 4–10 lux average is comfortable, while junctions, steps, and security areas may justify higher targets and tighter spacing.
Energy load, transformer headroom, and wiring
Total electrical load equals fixture count times watts per light. The calculator adds headroom to suggest a safer transformer size, helping reduce overheating and allowing future expansion. Wiring length increases with dual-side layouts, corners, and returns. Use the annual energy estimate (watts ÷ 1000 × hours × 365) to compare fixture wattages, timer settings, and operating cost across different design options.
Field verification before final purchasing
Use the results as a planning baseline, then validate with real fixtures after dark. Temporarily place lights at the suggested spacing, walk the route, and look for shadows from plants, fences, or grade changes. Increase overlap on curves and near steps. If the lux-based minimum exceeds the spacing-based count, consider higher-lumen fixtures, improved optics, or a more conservative utilization setting.
1) Should I use auto spacing or manual spacing?
Auto spacing is best when you know mount height and beam angle and want guidance. Manual spacing is best when you must match an existing pattern or a strict design standard.
2) Why does staggered sometimes look smoother than aligned?
Aligned layouts stack brightness at each station, creating brighter spots and darker gaps. Staggered layouts distribute fixtures between stations, improving uniformity along the walking line.
3) What utilization factor should I choose?
For shielded path lights, 0.15–0.35 is a practical planning range. Use lower values for obstructions and heavy shielding, and higher values for open, downward-focused optics.
4) What does the maintenance factor represent?
It represents output loss from dirt, lens aging, and voltage drop over time. Many installations use 0.75–0.90, with lower values for dusty areas or long cable runs.
5) Why is the final count the higher of two methods?
Spacing estimates continuity, while the lux estimate checks brightness across the full path area. Taking the higher count helps avoid under-lighting when fixtures are underpowered or conditions reduce output.
6) Can I use this for steps and landings?
Yes, but treat it as a baseline. Steps often need tighter spacing, better glare control, and higher target lux. Always verify with mockups and local safety guidance.