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Gutter coil calculator

Turn a measured gutter run into the coil a supplier actually sells: linear feet, pounds, and rolls. Free, no signup, and the downspout stock is calculated separately because it is a different coil.

By the Gutter IQ team · Published

The short answer, if that is all you came for

One linear foot of coil makes one linear foot of gutter. A seamless machine feeds the coil lengthwise and folds its width into the profile, so the width picks the gutter size and the length carries across one to one. Order your measured run plus waste. Then convert to pounds using the width and gauge, because aluminum coil is sold by weight.

Downspouts are a separate coil, in a thinner gauge and a different width, and are never subtracted from the gutter footage.

Your job

Measure along the eaves only. Rake edges carry no gutter.

Approved width is set by your machine make and model, not by the gutter name. Some 5 in machines run 11 7/8 in.

No industry standard exists. 10 percent is a starting point on a simple house.

On this page

The coil yield table

Aluminum coil is sold by weight, but you measure a job in feet. This is the conversion, and it is the number the counter at your supply house is working from too.

Aluminum gutter coil, weight per linear foot and feet per pound. Figures as published in supplier coil yield tables.
Coil widthFormsGaugePounds per ftFeet per pound
11 3/4 in5 in K-style.0270.3772.65
11 3/4 in5 in K-style.0320.4462.24
15 in6 in K-style.0270.4762.10
15 in6 in K-style.0320.5711.75
18 in7 in K-style.0270.5751.74
18 in7 in K-style.0320.6901.45

To read it: at 15 in and .027, every foot of gutter you hang consumes 0.476 lb of coil, and every pound of coil buys you 2.10 ft of gutter. A 350 lb full coil at that spec runs about 735 ft.

Why the table and not a formula. You can calculate coil weight from first principles as width times thickness times 12 times the density of aluminum, roughly 0.098 lb per cubic inch, and it lands within about one percent of the published figures. We use the published table anyway, because the point of the number is to match what your supplier quotes you. The formula is the fallback for widths the table does not cover.

Coil width by gutter profile

Coil width is what selects the gutter size. It is folded into the cross section as the coil runs through the machine.

GutterCoil widthNotes
5 in K-style11 3/4 inSome machines are set up for 11 7/8 in instead. Both are stocked.
6 in K-style15 inThe most consistent figure in the whole table. Every source agrees.
7 in K-style18 inSpecialty. Roll formed by shops that own the machine, brake formed elsewhere.
6 in reverse bead half round11 7/8 inUses about 21 percent less metal per foot than 6 in K-style.
Check your machine, not the chart. Approved coil width is a property of the machine make and model, and a machine set up for one width should not be assumed to form another profile correctly. The widths above are the near universal defaults, not a specification. Confirm yours once, then stop thinking about it.

Downspout coil is a separate calculation

This is the single most common way a coil order goes wrong. Downspout stock is not gutter coil in a different length. It is a thinner gauge, .019 is standard, in widths tied to the downspout size rather than the gutter size, and it is bought as its own roll.

DownspoutCoil widthGauge
2 x 3 rectangular10 1/2 in.019
3 x 4 rectangular13 3/4 in.019 or .024

Calculate it as drops times drop height, plus whatever you form yourself for offsets. Most shops buy elbows and offsets pre formed, so unless you are running your own, the drop height is the whole number. Downspout coil also comes in much heavier rolls than gutter coil, commonly around 500 lb and sometimes far more on production coil, and partial rolls are often not available at all.

Copper, and why it is priced differently

Copper is specified by weight per square foot rather than by thickness. 16 oz copper is about .0216 in thick and 20 oz is about .027 in, which makes 20 oz exactly 25 percent more metal. Because 16 oz is one pound per square foot by definition, the weight per linear foot of coil falls straight out of the width:

Coil width16 oz20 oz
11 3/4 in (5 in K-style)0.979 lb per ft1.224 lb per ft
15 in (6 in K-style)1.250 lb per ft1.563 lb per ft

Copper is commonly priced by the linear foot rather than by the pound, frequently with a minimum order, and full coils run around 500 lb. That is why the calculator leads with feet for copper and shows pounds second: feet is what you will be quoted on, pounds is what you need for freight and for a by-the-pound order.

Waste, and why nobody can tell you the right number

We looked for an industry standard waste percentage for gutter coil and there is not one. Estimating guidance says to measure the total run, add for corners and outlets, and round up to a roll size you can actually buy. That is the whole of it.

So treat any page that hands you a confident percentage with suspicion, this one included. Ten percent is a defensible starting point on a straightforward house. What actually drives your number is miter count, how many separate runs the roofline breaks into, and how disciplined your crew is about offcuts. After one season of tracking your own scrap you will have a better figure than any published average, and it is worth the tracking.

Keep the two inputs separate in your head. A waste percentage covers the losses you cannot itemise. An explicit allowance in feet covers the ones you can, like a long offset run you already know about. Inflating a known quantity by a waste factor double counts it, which is why the calculator adds the allowance after the percentage rather than before.

Common questions

How much coil do I need for 100 feet of gutter?

One hundred linear feet, plus waste. A seamless machine feeds coil lengthwise and folds the width into the profile, so one foot of coil produces one foot of gutter. The coil WIDTH selects the gutter size, it does not change the yield. What varies is the weight: 100 ft of 11 3/4 in coil at .027 is about 37.7 lb, while 100 ft of 15 in coil at .027 is about 47.6 lb.

What width coil do I need for 5 inch and 6 inch gutter?

11 3/4 in coil for 5 inch K-style, 15 in for 6 inch, and 18 in for 7 inch. Some machines are set up for 11 7/8 in on 5 inch instead, and coil width is approved per machine make and model rather than by the gutter name, so check the plate on your machine once and then trust it.

How many feet of gutter comes off a full coil of aluminum?

It depends on width and gauge. Using the published yield figures, a 350 lb full coil gives roughly 928 ft at 11 3/4 in and .027, or about 735 ft at 15 in and .027. Full coils are commonly quoted around 350 lb but range roughly 200 to 450 lb by supplier, so confirm the actual roll weight before you plan a season around a number.

Is downspout coil the same as gutter coil?

No, and this is the mistake that costs money. Downspout stock is thinner, .019 is standard, and comes in its own widths tied to the downspout size: 10 1/2 in coil forms 2x3 downspout, 13 3/4 in forms 3x4. It is a separate purchase and a separate calculation, never a subtraction from the gutter coil.

What waste percentage should I use for gutter coil?

There is no industry standard, and any page that gives you one as a fact is making it up. Estimating guidance says to measure the run, add for corners and outlets, and round up to the roll size you can actually buy. Ten percent is a reasonable starting point on a straightforward house. Raise it for cut up rooflines with many miters, and lower it once you have tracked your own scrap for a season, because your number is better than anyone else’s average.

How is copper gutter coil sold?

Copper is specified by weight per square foot rather than by thickness: 16 oz is about .0216 in and 20 oz is about .027 in, so 20 oz is 25 percent more metal. It is commonly priced by the linear foot rather than by the pound, often with a minimum order, and full coils run around 500 lb. The calculator above gives you both feet and pounds so you can order either way.

Does the coil calculator work with a satellite measurement?

In the Gutter IQ app, yes. It reads the eave length from the job’s existing measurement and fills the run in for you, so you never retype a number you already measured. On this public page you enter the run by hand, because there is no job attached to it.

Sources

Every figure on this page traces to one of these. Where two of them disagree, the page says so rather than averaging them.

The rest of the job, not just the measurement

Working out the coil is a two minute job. What decides whether the week pays is how many of the people who called while you were on a ladder ever heard back.

Front Desk: a business line that rings your phone

A real business phone number for your gutter company, built in. Place and answer calls, keep a shared call log the whole team can see, and text customers from a number that is not your cell. Incoming calls ring your iPhone with the standard call screen, on the lock screen, whether the app is open or closed. Every paid plan includes a real business phone number, free, with 120 minutes a month. See how Front Desk works.

Tax Central: expenses, receipts and W-9s

Track business expenses by job and by Schedule C category, so profit per job is a number you can see rather than one you work out in January. Scan a receipt with your camera, and collect a signed W-9 from every subcontractor you pay.

Timeclock: clock in from the truck, approve from the office

Your crew clocks in and out from the app with a location stamp on every punch, logs breaks as they take them, and submits each shift for approval when it ends. Owners, admins and team leaders approve or correct time for the people under them, and approved hours export as a CSV for payroll. Included with Platinum and Enterprise at no charge. On every other paid plan it is a flat monthly add-on for the whole company, not per user, and trials can use it during the trial. See what each plan includes.

Front Desk, Tax Central and Timeclock, answered

Does Gutter IQ include a business phone number?

Yes. Every paid plan includes a real business phone number at no extra cost, with 120 minutes a month. You pick your own local number in about thirty seconds. Calls and texts run from the app or a browser and always show the business number rather than a personal cell, and every call files itself against the customer it came from.

What does the AI receptionist actually do?

Turn on the AI receptionist and she answers when you cannot. She knows your services, your hours and your service area, books estimates straight onto your calendar, takes a message when the caller needs a person, and emails you the recording and a summary. Both sides are told the call is recorded, and recording can be switched off. It is optional: the business line works on its own with your team answering.

Do incoming calls ring the phone when the app is closed?

Yes, on iPhone. Front Desk calls ring with the standard iPhone call screen, on the lock screen, whether the app is open, in the background or closed, and appear in Recents like any other call. An Android build is in development with no release date announced.

Can I track expenses and 1099 paperwork in Gutter IQ?

Yes, in Tax Central. Track business expenses by job and by Schedule C category, scan a receipt with your camera to fill in the vendor, amount and category, and collect a signed W-9 from every subcontractor you pay. Taxpayer numbers are encrypted and shown only as the last four digits.

Does Gutter IQ have a timeclock for my crew?

Yes. Timeclock lets each person clock in and out from the app, pick the job they are on, and log breaks as they take them, with a location stamp on every punch. Shifts are submitted for approval when they end; owners and admins see everyone, team leaders see the people under them, and employees request corrections rather than editing the record. Approved hours export as a CSV for payroll. Included with Platinum and Enterprise at no charge. On every other paid plan it is a flat monthly add-on for the whole company, not per user, and trials can use it during the trial.

Stop retyping the number you already measured

In Gutter IQ, the coil calculator reads the eave length straight off the job measurement. Measure from satellite or on site, then order material without re-entering anything. 14 day free trial, no credit card.

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