Step 1: Get the length right
Length is the decision people get wrong most often, and it's the only one that's genuinely hard to fix later — matching strands sell out and get discontinued between seasons.
Two rules cover almost every case:
- Measure the path, not the space. Lights travel around a perimeter, across a yard, or up a trunk. The area of your patio tells you nothing directly.
- Add for sag. A gentle café drape adds about 15% to the straight-line distance. A deep swag adds 30%.
Then round up to the next whole strand — you can't cut string lights to length, so a 65-foot requirement means buying 96 feet in two 48-ft strands, not 1.35 strands.
Work out your length first →The free String Light Calculator handles patios, yard runs, tree wraps, and rooflines.Step 2: Pick a bulb type
Bulb shape sets the entire look, and the names are less confusing than they appear:
| Type | Bulb size | Best for | Look |
|---|---|---|---|
| S14 | Golf-ball sized | Patios, decks, pergolas | The classic café / bistro look |
| S11 / G40 | Slightly smaller / round | Smaller patios, balconies | Softer, more delicate café |
| G50 / G40 globe | Large round | Statement patios, event spaces | Bold, bulbous, warm |
| C9 | Large cone | Rooflines, Christmas displays | Traditional, high visibility |
| C7 | Medium cone | Rooflines, windows, railings | Traditional, slightly finer |
| Mini / fairy | Tiny | Tree wrapping, railings, shrubs | Fine and sparkly, subtle at distance |
The practical rule: the further away the viewer, the bigger the bulb should be. Mini lights on a roofline disappear from the street. S14 bulbs on a small balcony feel oversized up close.
Step 3: Choose bulb spacing
Spacing is the gap between bulbs along the wire. It changes the density of the look but not the length of lights you need:
- 6 inches — dense and bright. Good for tree wrapping and where you want a continuous glow.
- 12 inches — the standard for café lights and rooflines. Best all-rounder.
- 15–24 inches — airy and minimal. Fewer bulbs over the same distance, so a cheaper run, but sparse in a large space.
A 48-foot strand at 12-inch spacing has roughly 48 bulbs; the same 48 feet at 24-inch spacing has about 24. Same footage, half the light.
LED vs incandescent
| LED | Incandescent | |
|---|---|---|
| Power per bulb | ~0.5–1 W | ~5–11 W |
| Strands per chain | Often 5–15+ | Usually 2–3 |
| Lifespan | Very long | Shorter, bulbs fail regularly |
| Light quality | Varies — check colour temp | Naturally warm |
| Heat | Cool to touch | Hot — a burn and fire consideration |
| Cost | Higher upfront | Cheaper upfront, more to run |
LED is the better choice for nearly every outdoor use now, with one caveat: colour temperature. Look for around 2200K–2700K ("warm white" or "soft white"). Anything at 3000K and above starts to read as cold and clinical outdoors, which is the opposite of the effect most people want. Some LED sets are sold as "vintage" or "filament" style specifically to mimic the 2200K incandescent glow.
Weather ratings that actually matter
- Wet location rated — safe for direct exposure to rain and snow. This is what you want for anything hanging in the open.
- Damp location rated — for covered areas only: under a porch roof, a solid pergola, a covered patio. Not for open sky.
- UL or ETL listed — independently safety tested. Unlisted imports are a genuine risk with outdoor electrical products.
- IP44 and above — the international equivalent. IP44 handles splashing; IP65 handles direct jets and heavy rain.
Also check the wire itself. Heavier gauge commercial-grade wire (often marketed as SJTW) survives multiple seasons outdoors; thin consumer wire becomes brittle and cracks after a winter or two.
Shatterproof vs glass bulbs
Glass bulbs look better — there's no real argument about it. But if lights hang over a dining area, a walkway, a pool, or anywhere children play, shatterproof plastic is the sensible call. Modern plastic bulbs are much closer to glass in appearance than they were a few years ago, and they survive being knocked by a ladder or a branch.
What to buy, by project
| Project | Bulb | Spacing | Notes |
|---|---|---|---|
| Patio / deck café lighting | S14 LED, 2200K | 12 in | Shatterproof if over a table |
| Small balcony | S11 or G40 LED | 12 in | Smaller bulbs suit close viewing |
| Wrapping a tree | Mini / fairy LED | 4–6 in | Long runs — check chain limits |
| Roofline / Christmas | C9 or C7 LED | 12 in | Big bulbs read from the street |
| Railings and shrubs | Mini LED | 4–6 in | Low-voltage sets work well here |
| No outlet nearby | Solar LED | Any | Needs direct sun; dimmer output |
Frequently asked questions
How do I choose the right length for outdoor string lights?
Measure the actual path the lights will travel, add 15% for a gentle drape or 30% for a deep swag, then round up to the next whole strand. Never plan to cut string lights to length — standard sets can't be cut.
What size string lights are best for a patio?
S14 bulbs at 12-inch spacing are the standard café-patio choice, in warm 2200K LED. On a small balcony, smaller S11 or G40 bulbs suit the closer viewing distance better.
Are more expensive string lights worth it?
For outdoor use, usually yes — but for the wire, not the bulbs. Commercial-grade sets use heavier wire and better weather sealing, which is the difference between a set lasting one season and lasting five.
Should I buy solar string lights?
Only where running power is genuinely impractical. Solar sets are dimmer, depend on the panel getting several hours of direct sun, and fade through the night. Where an outlet exists, plug-in lights are more reliable.
What colour temperature should outdoor string lights be?
2200K to 2700K. That's the warm, amber glow people associate with café lighting. Anything 3000K and above reads cold outdoors and undercuts the effect.