18x30 RV Carport: Length, Height and Prices Sellers List
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An 18x30 carport covers 540 sq ft, 216 by 360 in. With the 3 to 5 ft buffer Eagle Carports advises, it holds an RV 25 to 27 ft long at most and leaves 4.75 ft each side of an 8.5 ft body. Sellers list legs from 7 to 14 ft, so leg height decides which RVs clear the roof.
On this page
Will your RV fit in an 18x30 carport?
An 18x30 RV carport is a steel carport 18 ft wide and 30 ft long, with a roof held up by legs that sellers list as the third number in a size such as 18x30x12. Table 1 sets each RV class against that footprint, using the class ranges from Storage.com, a storage-company table updated 2026-06-09. For other footprints, use the carport sizing guide. For the same classes at other sizes, see RV carport sizes by class.
In an 18x30, a Class B motorhome fits with room to spare, and a Class C motorhome fits up to about 25 to 27 ft. A Class A motorhome fits only at 26 to 27 ft, and a fifth wheel or toy hauler fits up to 25 to 27 ft. A travel trailer fits when its body plus the hitch tongue stays within 25 to 27 ft, which is a body of 21 to 23 ft.
| RV class | Length (ft) | Width (ft) | Height (ft) | Length test, 30 ft | Side room (ft each side) | Height test, 12 ft leg | Height test, 13 ft leg |
|---|---|---|---|---|---|---|---|
| Class A motorhome | 26 to 45 | 8 to 8.5 | 12 to 13.5 | Only 26 to 27 ft fits. 45 ft is 15 ft over. | 4.75 to 5 | 12 ft leaves none. 13.5 ft is 1.5 ft over. | 12 ft leaves 1 ft. 13.5 ft is 0.5 ft over. |
| Class B motorhome | 17 to 23 | 7 to 8 | 9 to 10 | Fits. 23 ft leaves 7 ft. | 5 to 5.5 | 9 ft leaves 3 ft. 10 ft leaves 2 ft. | 9 ft leaves 4 ft. 10 ft leaves 3 ft. |
| Class C motorhome | 20 to 33 | 8 to 8.5 | 10 to 12 | Fits up to 25 to 27 ft. 33 ft is 3 ft over. | 4.75 to 5 | 10 ft leaves 2 ft. 12 ft leaves none. | 10 ft leaves 3 ft. 12 ft leaves 1 ft. |
| Fifth wheel | 22 to 40 | 8 to 8.5 | 12 to 13.5 | Fits up to 25 to 27 ft. 40 ft is 10 ft over. | 4.75 to 5 | 12 ft leaves none. 13.5 ft is 1.5 ft over. | 12 ft leaves 1 ft. 13.5 ft is 0.5 ft over. |
| Travel trailer | 12 to 35 | 8 to 8.5 | 9 to 11 | Body up to 21 to 23 ft with a 4 ft tongue. A 35 ft body plus tongue is 39 ft, 9 ft over. | 4.75 to 5 | 9 ft leaves 3 ft. 11 ft leaves 1 ft. | 9 ft leaves 4 ft. 11 ft leaves 2 ft. |
| Toy hauler | 24 to 44 | 8 to 8.5 | 11 to 13 | Fits up to 25 to 27 ft. 44 ft is 14 ft over. | 4.75 to 5 | 11 ft leaves 1 ft. 13 ft is 1 ft over. | 11 ft leaves 2 ft. 13 ft leaves none. |
Class ranges come from a storage-company table, updated 2026-06-09, and not from RV makers. Your RV can sit outside them.
Results use the class ranges or the measurements you enter and the nominal 18 ft by 30 ft footprint. Measure your RV with its roof gear and confirm the entry height with your seller.
Length: 25 to 27 ft with the buffer
Length sets the limit in an 18x30. Eagle Carports advises adding at least 3 to 5 ft to an RV's length, which leaves a longest RV of 25 to 27 ft in 30 ft. The buffer is the spare length in front of and behind the RV, so the longest RV moves with the rule each seller states. Table 2 sets the sources side by side.
A travel trailer counts its hitch tongue, which Storage.com puts at 2 to 4 ft and leaves out of the listed body length. With a 4 ft tongue, the body can run 21 to 23 ft. A Class A motorhome runs 26 to 45 ft, so only the 26 to 27 ft models clear the buffer.
| Source | Rule as the source states it | Longest RV in 30 ft | How this page uses it |
|---|---|---|---|
| Eagle Carports, RV size guide (read 2026-10-06) | "Add at least 3-5 feet" to the RV length | 25 to 27 ft | The rule this page and the Fit Checker use |
| Eagle Carports, same guide | "add 4 to 8 feet so you can pull in easily" | 22 to 26 ft | Shown for comparison |
| Pro Metal Buildings, "Measure Your RV" (read 2026-10-06) | "Add 2-3 extra feet" | 27 to 28 ft | Shown for comparison |
| Storage.com, travel-trailer note | Hitch tongue adds 2 to 4 ft and is not in the listed length | Body up to 21 to 23 ft at a 3 to 5 ft buffer and a 4 ft tongue | Travel trailers, as the Fit Checker counts them |
| Eagle Carports pairing: 12x25x10 for a travel trailer of 20 to 25 ft | Pairing on its size chart | A 25 ft trailer with a 4 ft tongue is 29 ft, 1 ft of spare length. A 20 ft one leaves 6 ft | A worked case for this size |
Width: side room and slide-outs
An 18 ft width leaves 4.75 ft (57 in) on each side of an 8.5 ft body, because 18 minus 8.5, divided by 2, is 4.75. An 8 ft body leaves 5 ft each side. An 8.5 ft body is 102 in wide, the width limit the Federal Highway Administration gives for commercial motor vehicles and the top of each Storage.com width range.
Slide-outs use that room. Storage.com says an open slide-out adds 2 to 3 ft or more to the total width. One 3 ft slide-out brings an 8.5 ft body to 11.5 ft and leaves 6.5 ft in total. Two 3 ft slide-outs bring it to 14.5 ft and leave 3.5 ft. Eagle Carports suggests an 18 ft wide carport for extended slide-outs, and American Steel Carports says slide-outs on both sides likely need 18 to 24 ft.
The plan view below draws a 26 ft RV with an 8.5 ft body in the 18 ft by 30 ft footprint.
Height: leg, roof gear and the clear opening
Height is where the listed 18x30 sizes differ most, because sellers list legs from 7 to 14 ft. The leg is the vertical post, not the peak, and American Steel Carports says a 12 ft side leg means about 14 ft at the center. The clear opening, the height at the entry, can be lower than the leg, so ask the seller for it.
Roof gear such as an air conditioner, solar panels or a dish can add 8 to 12 in or more to a listed RV height, says American Steel Carports. For clearance above the roof, American Steel advises 2 to 3 ft, Pro Metal Buildings 1 to 2 ft and Engineered Metal Buildings 6 to 12 in. The sources differ, so Table 3 shows the plain margins and leaves the buffer to you and your seller.
| Leg height | Class B (9 to 10) | Class C (10 to 12) | Travel trailer (9 to 11) | Toy hauler (11 to 13) | Class A, fifth wheel (12 to 13.5) | Pop-up (4 to 9) |
|---|---|---|---|---|---|---|
| 7 ft | 2 to 3 ft over | 3 to 5 ft over | 2 to 4 ft over | 4 to 6 ft over | 5 to 6.5 ft over | 2 ft over to 3 ft room |
| 10 ft | 0 to 1 ft room | 0 to 2 ft over | 1 ft over to 1 ft room | 1 to 3 ft over | 2 to 3.5 ft over | 1 to 6 ft room |
| 12 ft | 2 to 3 ft room | 0 to 2 ft room | 1 to 3 ft room | 1 ft over to 1 ft room | 0 to 1.5 ft over | 3 to 8 ft room |
| 13 ft | 3 to 4 ft room | 1 to 3 ft room | 2 to 4 ft room | 0 to 2 ft room | 0.5 ft over to 1 ft room | 4 to 9 ft room |
| 14 ft | 4 to 5 ft room | 2 to 4 ft room | 3 to 5 ft room | 1 to 3 ft room | 0.5 to 2 ft room | 5 to 10 ft room |
The elevation drawing sets the same five legs against the height range of each RV class.
Check your RV against an 18x30 carport
The RV Fit Checker tests one RV against the 18x30 footprint. Enter the length, width and height, add slide-outs and roof gear, and pick a leg height. It returns a verdict for length, width and height with the arithmetic beside each, then names the first size on a short ladder that clears all three. It starts on a 26.5 ft Class C motorhome, so a result shows before you type.
Worked examples, computed with the same arithmetic as the Fit Checker
| Example | Inputs | Length | Width | Height | Overall and next size |
|---|---|---|---|---|---|
| WE1: Class C motorhome, class midpoints (the tool default) | length 26.5; width 8.25; height 11; slide-outs 1 x 3; leg 12; opening blank | Fits with limits. 26.5 ft used, 3.5 ft spare | Fits with limits. 11.25 ft wide, 6.75 ft left | Fits with limits. 11 ft against 12 ft, margin 1 ft | Fits with limits. Next size: this size clears all three |
| WE2: 24 ft Class C | length 24; width 8.5; height 10; slide-outs 1 x 3; leg 12; opening blank | Fits. 24 ft used, 6 ft spare | Fits with limits. 11.5 ft wide, 6.5 ft left | Fits. 10 ft against 12 ft, margin 2 ft | Fits with limits. Next size: this size clears all three |
| WE3: Travel trailer, 22 ft listed body length, 10 ft listed height with roof gear | length 22 + 4 tongue; width 8; height 10 + 1 roof gear; slide-outs 0; leg 12; opening blank | Fits with limits. 26 ft used, 4 ft spare | Fits. 8 ft wide, 10 ft left | Fits with limits. 11 ft against 12 ft, margin 1 ft | Fits with limits. Next size: this size clears all three |
| WE4: Fifth wheel, 31 ft, one slide-out | length 31; width 8.25; height 12.75; slide-outs 1 x 3; leg 13; opening blank | Does not fit. 31 ft used, -1 ft spare | Fits with limits. 11.25 ft wide, 6.75 ft left | Check height. 12.75 ft against 13 ft, margin 0.25 ft | Does not fit. Next size: 18x35x14 |
| WE5: 30 ft Class A, slide-outs both sides | length 30; width 8.5; height 13.5; slide-outs 2 x 3; leg 12; opening blank | Check length. 30 ft used, 0 ft spare | Fits with limits. 14.5 ft wide, 3.5 ft left | Does not fit. 13.5 ft against 12 ft, margin -1.5 ft | Does not fit. Next size: 18x35x14 |
| Test | Rule | Verdict | Source |
|---|---|---|---|
| Length | Used length = length + tongue (4 ft when the box is on). Spare = 30 minus used length. | Spare 5 ft or more: Fits. 3 up to 5 ft: Fits with limits. 0 up to 3 ft: Check length. Below 0: Does not fit. | Eagle Carports: add at least 3 to 5 ft to the RV's length. |
| Width | Extended width = width + slide-outs x depth. Room = 18 minus extended width. | Over 18 ft: Does not fit. No slide-outs: Fits. One side: Fits with limits. Both sides: Fits with limits at 18 ft wide or more. | Storage.com for slide-out depth. American Steel Carports: 18 to 24 ft with slide-outs on both sides. |
| Height | Effective height = height + roof gear (1 ft when the box is on). Margin = opening minus effective height. The opening is the entered value or the leg height. | Margin below 0: Does not fit. 0 up to 0.5 ft: Check height. 0.5 up to 2 ft: Fits with limits. 2 ft or more: Fits. | American Steel Carports: 2 to 3 ft. Engineered Metal Buildings: 6 to 12 in. |
| Overall | The most severe of the three words. | The Fit Checker names the first size on its ladder where all three words are Fits or Fits with limits, each entry scored with its own leg height. | Listings and guides read on the date shown. |
What leg heights do sellers list for an 18x30 RV carport?
Sellers list 18x30 RV carports with legs from 7 to 14 ft. Tables 4 and 5 group the ten priced listings read on 2026-10-06 by leg height, each with the seller's own scope. A leg is the number printed in the seller's product title or specification line.
| Seller and listing | Leg (ft) | Listed price | Scope as listed | Per sq ft at 540 |
|---|---|---|---|---|
| Coast to Coast Carports"18x30 RV Carport" (regular roof) | 7 | $3,065.00 | Starting price; free delivery and installation | $5.68 |
| Engineered Metal Buildings"18x30x7 RV Carport" | 7 | $3,745.00 | Starting price; delivery and installation included; 14-gauge tubing, 29-gauge panels | $6.94 |
| Keen's Buildings"18x30 Carport / RV Carport" | not stated (6 to 20 ft offered) | $3,690.00 | Installed price; free delivery; rounded roof; two quarter panels | $6.83 |
| Triple A Steel Structures"18x30 RV Carport" (one panel per side) | 10 | $3,895.00 | Starting price; delivery and installation included; regular roof | $7.21 |
A 7 ft leg is 2 to 6.5 ft lower than every motorhome, trailer and toy hauler class in Table 3, so only the lowest campers fit under it. Keen's Buildings offers heights from 6 to 20 ft on its 18x30 RV carport page and does not say which height its price covers.
| Seller and listing | Leg (ft) | Listed price | Scope as listed | Per sq ft at 540 |
|---|---|---|---|---|
| Keen's Buildings"18x30x12 Carport" | 12 | $3,200.00 | Installed price; free delivery; standard rounded roof; vertical and A-frame offered | $5.93 |
| Wolf Steel Buildings"R1-18x30 RV Metal Building" | 12 | $17,060.00 (turnkey $19,341.00) | Closed sides; vertical roof; 14-gauge frame; turnkey adds delivery, installation, labor, taxes | $31.59 |
| Coast to Coast Carports"18x30 Metal RV Carport" | 13 | $7,005.00 | Starting price; vertical roof; open sides; free delivery and installation | $12.97 |
| SteelCarports.com, GetCarports.com and Panhandle Metals18x30x13 RV carports | 13 | $8,585.00 (the same figure on all three pages) | Roof as listed: vertical (SteelCarports.com, GetCarports.com) or A-frame with gable ends (Panhandle Metals); GetCarports.com and Panhandle Metals state a 14-gauge frame and 29-gauge panels; delivery and installation included | $15.90 |
Prices are listed by each seller on the date shown and change often. A listed price is not a quote.
Thirteen feet is the leg listed most often: four of the ten priced listings read on 2026-10-06. SteelCarports.com, GetCarports.com and Panhandle Metals show the same $8,585 for an 18x30x13 on their own pages. The tallest leg read is 14 ft, on an 18x30x14 from Pacific Buildings Inc. For metal frame, gauge and roof style at this size, see all-metal RV carports at 18x30.
The chart plots the ten priced listings against leg height.
How much does an 18x30 RV carport cost?
Sellers listed 18x30 RV carports from $3,065 to $17,060 on 2026-10-06, which is $5.68 to $31.59 per sq ft at 540 sq ft. Each per sq ft figure is the listed price divided by 540.
The range reflects what each price covers. Coast to Coast Carports lists $3,065 for a 7 ft leg with a regular roof and $7,005 for a 13 ft leg with a vertical roof and open sides. Wolf Steel Buildings lists $17,060 for a closed-sided building with a 12 ft leg and a 14-gauge frame, and $19,341 turnkey, which adds delivery, installation, labor and taxes. Compare scope before price, and ask each seller what its price includes.
These are listed prices for the size.
What size comes after the 18x30 for a longer RV?
A longer RV needs more length, and a wider body with slide-outs needs more width. At the 3 to 5 ft buffer, a 30 ft RV needs a carport 33 to 35 ft long, so 18x35 is the first size up. Table 6 gives the longest RV and the side room at each size.
Eagle Carports pairs a Class C motorhome or fifth wheel of 30 to 35 ft with an 18x35x14, and a Class A motorhome or toy hauler of 35 to 45 ft with a 20x45x16. At a 3 to 5 ft buffer, an 18x35 holds an RV 30 to 32 ft long and a 20x45 holds one 40 to 42 ft long, so Eagle's own top lengths leave no buffer under its rule. For the same length with 2 ft more width, see a 20x30 carport for a mid-length RV.
| Size | Where the pairing comes from | Longest RV at 3 to 5 ft buffer (ft) | Side room, 8.5 ft body (ft each side) | Note |
|---|---|---|---|---|
| 18x30 | This page | 25 to 27 | 4.75 | Table 1. |
| 20x30 | General Steel, RV Carport Building Packages (read 2026-10-06) | 25 to 27 | 5.75 | Same length, 2 ft wider. General Steel says its 20x30 is "large enough to accommodate a Class A RV", which is a seller claim. A Class A runs 26 to 45 ft, and a 20x30 holds 25 to 27 ft at a 3 to 5 ft buffer. |
| 18x35x14 | Eagle Carports size guide: Class C or fifth wheel, 30 to 35 ft | 30 to 32 | 4.75 | Eagle pairs a 35 ft RV with a 35 ft carport, which leaves no buffer under its own 3 to 5 ft rule. |
| 18x40 | Gold Tier Structures 18x40x12 and 18x40x14 listings (read 2026-10-05) | 35 to 37 | 4.75 | Coast to Coast Carports recommends 18 ft wide for an RV or camper. |
| 16x40 | Seller listings on the 16x40 RV carport page | 35 to 37 | 3.75 | The 16 ft width leaves 3.75 ft each side of an 8.5 ft body. 16x40 RV carport size guide. |
| 20x45x16 | Eagle Carports size guide: Class A or toy hauler, 35 to 45 ft | 40 to 42 | 5.75 | The same buffer rule leaves the top of Eagle's own range at no buffer. |
Does an 18x30 RV carport need a permit?
An 18x30 carport is 540 sq ft, which is 2.7 times the 200 sq ft line in the 2021 International Residential Code section R105.2. That section exempts one-story detached accessory structures of 200 sq ft or less from a building permit. Local rules differ. For the rules by jurisdiction, see permit rules and thresholds.
| Source or size | Area (sq ft) | Multiple of 200 sq ft |
|---|---|---|
| IRC 2021 R105.2, exempt accessory structure (Grant County, Washington) | 200 | 1.0 |
| 18x30 carport (this page) | 540 | 2.7 |
| 20x30 carport | 600 | 3.0 |
| 16x40 carport | 640 | 3.2 |
This table gives general information from the code cited above. Confirm current requirements with your local building department before beginning construction.
Frequently asked questions
An RV up to 25 to 27 ft long fits in an 18x30 carport with the 3 to 5 ft buffer Eagle Carports advises. A travel trailer counts its hitch tongue, which adds 2 to 4 ft, so its body can run about 21 to 23 ft. Measure your own RV first.
An 18 ft width holds an RV body up to 8.5 ft wide with 4.75 ft on each side. One 3 ft slide-out open leaves 6.5 ft in total, and both open leave 3.5 ft. Check the open width of your RV against 18 ft before you order.
Sellers list this size with legs from 7 to 14 ft, and your RV's height plus roof gear and a buffer picks the right one. Class A motorhomes and fifth wheels stand 12 to 13.5 ft tall, so a 12 ft leg is level with the lowest and 1.5 ft under the tallest, and a 14 ft leg leaves 0.5 to 2 ft.
Sellers listed 18x30 RV carports from $3,065 to $17,060 on 2026-10-06, which is $5.68 to $31.59 per sq ft at 540 sq ft. The range reflects different legs, roofs, sides and installation terms, so compare scope before price. A listed price is not a quote.
An 18x30 is 540 sq ft, which is 2.7 times the 200 sq ft exemption line in IRC 2021 section R105.2. That line covers one-story detached accessory structures, and local rules differ. Confirm what applies with your local building department before you order.
A 30 ft RV leaves no buffer in a 30 ft deep carport, so it misses the 3 to 5 ft Eagle advises. Class A motorhomes run 26 to 45 ft, and only the 26 to 27 ft ones clear the length rule. At 12 to 13.5 ft tall they also need a leg of 14 ft or more.
A 30 ft RV needs a carport 33 to 35 ft long, so 18x35 is the first size up. That follows the 3 to 5 ft buffer Eagle Carports advises, and Eagle pairs a 30 to 35 ft Class C or fifth wheel with an 18x35x14. Check the height and the width with slide-outs.
Next steps
Measure your RV from bumper or hitch to the far end, then add the 3 to 5 ft buffer and compare the total with 30 ft. Measure the height with roof gear and the width with slide-outs open. Ask each seller for the leg height, the clear opening and what the price covers, then request a quote.
For other footprints, see the CarportBay carport sizing guide.
Have your RV's length, height and width ready, and ask each seller for the leg height and what its price covers.
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Sources
Each price, size and guide figure above is quoted from the source named, on the read date. Seller pages are cited by name and date. Codes and federal rules link to their publisher.
- Storage.com, Average RV Sizes: Dimensions by Type [2026] (updated 2026-06-09; read 2026-10-06)
- Extra Space Storage, RV Dimensions by Type (updated 2026-06-30; read 2026-10-05)
- Federal Highway Administration, Freight Management and Operations, Questions and Answers About Vehicle Size and Weight (read 2026-10-06)
- Grant County, Washington, Copy of the 2021 International Residential Code, section R105.2 (work exempt from permit) (read 2026-10-06)
- Eagle Carports, Carport size guide for RVs and trucks (read 2026-10-06)
- Pro Metal Buildings, Measure Your RV for a Carport or Metal Cover (read 2026-10-06)
- American Steel Carports, RV Carport Height Guide (read 2026-10-06)
- Engineered Metal Buildings, RV Carport Height Guide (read 2026-10-06)
- Coast to Coast Carports, Metal carports (read 2026-10-05)
- General Steel, RV Carport Building Packages: Popular Sizes (read 2026-10-06)
- Coast to Coast Carports, 18x30 RV Carport (regular roof) (read 2026-10-06)
- Engineered Metal Buildings, 18x30x7 RV Carport (read 2026-10-06)
- Keen's Buildings, 18x30 Carport / RV Carport (read 2026-10-06)
- Triple A Steel Structures, 18x30 RV Carport Regular Roof Style with One Panel per Side (read 2026-10-06)
- Keen's Buildings, 18x30x12 Carport (read 2026-10-06)
- Wolf Steel Buildings, R1-18x30 RV Metal Building (read 2026-10-06)
- Coast to Coast Carports, 18x30 Metal RV Carport (read 2026-10-06)
- SteelCarports.com, 18x30 Vertical RV Carport (read 2026-10-06)
- GetCarports.com, 18'x30'x13' Metal RV Carport (read 2026-10-06)
- Panhandle Metals, 18x30x13 RV Carport (read 2026-10-06)
- Pacific Buildings Inc., 18'x30'x14' RV Carport (read 2026-10-06)
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