Free planning tool

How many string lights do you need?

Enter the space and pick a hanging pattern. You get feet of lights, bulbs, uplights and a picture of the layout.

For straight runs, count the runs (length divided by spacing, plus one) and multiply by the width, then add about 10% for sag and the drop to power. A 20 by 40 foot tent with runs every 6 feet needs about 154 feet of string lights. Uplights: roughly one every 8 feet of wall.

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Length

Width

Pattern

Space between runs

Closer runs read as a glowing ceiling; wider runs feel airy.

Extra for sag and drops to power

Bulb spacing on the strand

Check the strand you rent; 12 inches is common.

One uplight every

ft of wall

154 ft

String lights

140 ft of runs + 10% slack

154

Bulbs

One every 12"

Uplights

Around the walls

7 runs. Lights need a power point near one end of each run.

Rough rental cost at our catalog prices

2 × Bistro string lights(estimate)	$165
15 × LED uplight	$578
Items total	$743

Items only, before delivery, setup and fees. Prices are based on local rental companies' published rates plus our booking fee; the rental company confirms the final quote for your date.

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How it works

Using the string light and uplight calculator

Step 1Measure the spaceLength and width in feet.
Step 2Pick a patternStraight, zigzag, starburst or edge.
Step 3Set spacing and slackHow dense, and extra for sag.
Step 4Price the lightsStrands and uplights, then a quote.

The method

How we work out the numbers

Straight runs: (length ÷ spacing, rounded down, plus one) runs, each as long as the width. Zigzag: one diagonal leg for every spacing step along the length, each leg √(width² + spacing²). Starburst: eight runs from the centre to the four corners and four wall midpoints. Perimeter: twice length plus width.

We then add your slack percentage. Bulbs are total feet × 12 ÷ bulb spacing in inches. Uplights are the perimeter divided by your spacing. Our catalog prices string lights per 100 ft strand, so the rough price rounds up to whole strands.

Sizing a tent first? Use the tent size calculator. Planning the whole night? The timeline builder reminds you when to book lighting.

Questions

String light and uplight calculator: FAQ

How many feet of string lights do I need for a 20 x 40 tent?

With straight runs across the 20' width every 6', a 20' x 40' tent takes 7 runs, or 140 ft. Add about 10% for sag and the drop to power and you need about 154 ft. A zigzag or starburst uses a different amount; the calculator shows each.

How far apart should string light runs be?

There's no single rule. Runs 4' to 6' apart feel like a glowing ceiling, and 8' to 10' apart feel open and airy. Pick a gap and the calculator does the rest.

Why add extra length?

Lights sag between poles and need to drop down to an outlet or generator. The calculator adds 10% by default, and you can change it.

How many uplights do I need?

A common approach is one uplight every 6' to 10' of wall you want to wash with colour. The calculator starts at one every 8' around the whole space; lower it for a fuller look.

Do string lights need a power source nearby?

Yes. Each run needs to reach an outlet or generator, and long runs may need more than one circuit. Tell your rental company where power is so they can plan cords.

When do I need lights at an evening event?

Once the sun goes down. Sunset in Chicago is early in winter and late in June, so check your date's sunset time when you plan.

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