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The Short Answer
If you own the standard Fractal Design North, you can fit a 360mm radiator in the front, a 240mm radiator on top, and a 120mm radiator in the rear. If you own the Fractal Design North XL, you can fit up to a 420mm radiator in the front, up to a 360mm radiator on top, and a 140mm radiator in the rear. For most builders using an AIO liquid cooler, that means a 240mm or 360mm AIO in the front of the standard North is the safest bet, while the North XL gives you headroom for a 420mm front mount.
The limitation is not just length. The standard North has tight clearance on top due to the motherboard, RAM, and the wood front trim structure. Fractal limits the top to 240mm and restricts total thickness to about 55mm including fans. The front can take thicker radiators, but you will lose GPU length if you go too thick or push-pull. In the North XL, both front and top have more clearance, which is why it is the better choice if you plan a 280mm or 420mm cooler or a thick custom loop. As of 2026, these are the official specs Fractal lists for both cases, and they match what installers are actually able to fit without modification.
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Standard Sizes
PC radiators are named by fan size, not by their exact physical length. A 240mm radiator holds two 120mm fans, a 280mm holds two 140mm fans, a 360mm holds three 120mm fans, and so on. The actual radiator is always a little longer than the name suggests because of end tanks and mounting tabs. Thickness also matters for fit. Most AIO coolers use a slim 27mm to 30mm radiator plus 25mm fans for a total stack of 52mm to 55mm.
| Radiator Size | Fan Configuration | Nominal Size | Actual Radiator Dimensions (L x W x H) | Fits Fractal North | Fits Fractal North XL |
|---|---|---|---|---|---|
| 120mm | 1 x 120mm | 120mm | 6.06 x 4.72 x 1.06 in / 15.4 x 12.0 x 2.7 cm (approx. 154 x 120 x 27mm) | Front, Top, Rear | Front, Top, Rear |
| 140mm | 1 x 140mm | 140mm | 6.73 x 5.51 x 1.06 in / 17.1 x 14.0 x 2.7 cm (approx. 171 x 140 x 27mm) | Front only | Front, Top, Rear |
| 240mm | 2 x 120mm | 240mm | 10.91 x 4.72 x 1.06 in / 27.7 x 12.0 x 2.7 cm (approx. 277 x 120 x 27mm) | Front, Top (max top size) | Front, Top |
| 280mm | 2 x 140mm | 280mm | 12.28 x 5.51 x 1.06 in / 31.2 x 14.0 x 2.7 cm (approx. 312 x 140 x 27mm) | Front only | Front, Top |
| 360mm | 3 x 120mm | 360mm | 15.63 x 4.72 x 1.06 in / 39.7 x 12.0 x 2.7 cm (approx. 397 x 120 x 27mm) | Front only (max front size) | Front, Top (max top size) |
| 420mm | 3 x 140mm | 420mm | 17.99 x 5.51 x 1.06 in / 45.7 x 14.0 x 2.7 cm (approx. 457 x 140 x 27mm) | No | Front only (max front size, requires 140mm fan mounts) |
Standard AIO thickness is 27mm for most brands like Corsair, NZXT, Arctic, and Lian Li. Some performance radiators are 30mm, 38mm, or 45mm thick before fans. Add 25mm for standard fans, or 15mm for slim fans if you need to save clearance. Weight for a typical 240mm AIO is 1.8 to 2.4 pounds (0.8 to 1.1 kg) without coolant, and a 360mm AIO is 2.2 to 3.1 pounds (1.0 to 1.4 kg). Custom loop radiators vary more, from 27mm slim to 60mm extra-thick.
How to Measure Your Space
Before you buy, measure the case itself rather than trusting the box length alone. A 360mm radiator that is 397mm long will not fit in a 395mm space, and fan thickness will make or break a top mount.
- Identify your exact model. Check the label on the rear or the box. The standard North is 447 x 215 x 469mm (17.6 x 8.46 x 18.46 in) and the North XL is 503 x 240 x 509mm (19.8 x 9.45 x 20.04 in). The XL is about 2.2 inches wider and 1.6 inches taller.
- Measure front clearance. Remove the front wood panel and dust filter. Measure from the inside of the front bracket to the leading edge of your GPU. For reference, the standard North allows up to 355mm GPU length with a front fan, but a 55mm thick radiator plus fan stack will reduce that to about 300mm to 315mm. The North XL allows up to 380mm GPU length with a front fan, and about 325mm to 340mm with a thick front radiator.
- Measure top clearance. This is the critical one. With the side panel off, measure from the top fan bracket down to the top of your RAM sticks and to the top of the motherboard VRM heatsink. In the standard North, you have about 55mm total for radiator plus fans on top. If your RAM is taller than 36mm, many 240mm radiators will touch the RAM. Use low-profile RAM under 34mm for top mounts.
- Measure thickness budget. Stack your intended radiator and fan and measure the total. A typical 27mm radiator plus 25mm fan is 52mm. A 30mm radiator plus 25mm fan is 55mm, which is the practical limit for the top of the standard North. For the front, up to 75mm total is usually possible before you intrude heavily on GPU space.
- Check fan mount spacing. Hold a 120mm or 140mm fan against the bracket to confirm screw alignment. The standard North front supports both 120mm and 140mm spacing, the top supports only 120mm spacing, and the rear supports 120mm. The North XL front supports 120mm and 140mm, the top supports both, and the rear supports 120mm and 140mm.
- Account for tubes and fittings. AIO tubes need about 1.5 to 2 inches of bend radius at the radiator end. Make sure the tube exit side will not hit the top of the case or the rear fan. For custom loops, add 10mm to 15mm for fittings on top of radiator thickness.
- Dry fit with fans first. Mount fans to the bracket, reinstall the bracket, and check motherboard and RAM contact before you mount the radiator. It is easier to adjust now than with a filled radiator.
By Room or Use Case
Front Mount in the Standard North: Best for 240mm and 360mm AIOs
The front is the most forgiving position in the standard North. It officially supports 120mm, 140mm, 240mm, 280mm, and 360mm. For a gaming build with a long GPU, a 240mm front radiator is the easiest install and leaves maximum GPU length. A 360mm front radiator gives the most cooling area and fits without case modification, but choose a slim 27mm to 30mm radiator if your GPU is longer than 310mm. Mount the fans as intake behind the front panel and the radiator inside the chassis for the cleanest tube run. If you use a 280mm radiator in front, use 140mm fans and keep total thickness under 65mm to preserve airflow from the included 140mm Aspect PWM fans.
Top Mount in the Standard North: Limited to 240mm
The top of the standard North only supports a 240mm radiator, and only with careful component choice. Fractal specifies 240mm maximum on top, and total height including fans must stay under about 55mm. That means a 27mm radiator with 25mm fans is the practical maximum. Avoid 280mm or 360mm here, they will not line up with the mounting holes and will hit the wood front frame. Use low-profile RAM at 33mm to 35mm tall and check VRM heatsink height on your motherboard. Top mount is best for a clean front aesthetic or if you want to keep the two included 140mm front fans for airflow and still add liquid cooling. If your RAM is taller than 42mm, plan to front mount instead.
North XL Front and Top: For 360mm, 420mm, and Thick Radiators
The North XL was designed for larger cooling. Front supports up to 420mm, which is three 140mm fans, as well as 360mm, 280mm, and 240mm. Top supports up to 360mm and on many builds will also accept 280mm. The extra width gives about 25mm more top clearance than the standard North, so a 30mm radiator with 25mm fans fits comfortably on top, and even a 38mm radiator can work with low-profile RAM. If you want a 420mm AIO, you must use the front position in the XL with 140mm fan mounts. For a 360mm top mount in the XL, keep GPU and motherboard choice in mind but you will not need to sacrifice RAM height as aggressively. This case is also the one to choose if you want a thick 45mm to 60mm custom loop radiator in the front without limiting GPU selection.
Rear Mount and Custom Loop with Distroplate
The rear fan position supports a 120mm radiator in the standard North and a 120mm or 140mm radiator in the North XL. This is useful for a small 120mm AIO on a CPU or for an extra radiator in a custom loop, but it is not a primary cooler for a modern CPU over 125 watts. It mounts to the side and is designed to pair with a front radiator up to 360mm in the standard North. If you run a distroplate, plan radiator thickness carefully because the plate itself consumes about 25mm to 30mm of interior width. In that setup, a 30mm thick front radiator with standard 25mm fans is the sweet spot.
Common Sizing Mistakes
The most frequent mistake is assuming any 360mm will fit on top of the standard North. It will not. The top bracket is 240mm only, and forcing a larger radiator will block the front I/O cables and wood panel mounts. Second is ignoring RAM height. Tall RGB RAM at 44mm to 51mm will collide with a top radiator and fans, even if the radiator length is correct. Third is buying a 420mm cooler for the standard North. There are no 140mm x 3 mounting holes on top and the front is about 25mm too short for a 457mm long 420mm radiator. Fourth is stacking a thick radiator with standard fans in the front and then finding the GPU no longer fits. Always subtract radiator plus fan thickness from your available GPU length. Fifth is forgetting to include fittings. A radiator that measures 277mm long may need another 15mm for compression fittings, which pushes it into the top frame or front filter. Finally, mixing up fan size and radiator size causes returns. A 280mm radiator needs a case that supports 140mm fan spacing, which the top of the standard North does not.
FAQ
What is the largest radiator that fits in the Fractal North without modification?
In the standard Fractal North, the largest is a 360mm radiator in the front, which is three 120mm fans. The largest on top is 240mm, and the rear is 120mm. You cannot fit a 360mm on top or a 420mm anywhere in the standard model without drilling new holes. In the North XL, the largest is a 420mm in the front and a 360mm on top.
Can I put a 280mm radiator on top of the regular Fractal North?
No. The top bracket in the regular North only has mounting holes for 120mm fans, so a 280mm radiator that needs 140mm spacing will not bolt in. Even if you could adapt it, the width would interfere with the side panel and the length would hit the front panel frame. Use a 240mm on top or move a 280mm to the front, where 140mm spacing is supported. The North XL does support a 280mm on top.
How thick can my radiator be in the Fractal North?
On top of the standard North, keep total thickness including fans at or under 55mm. That typically means a 27mm radiator with 25mm fans. In the front, you have more room, up to about 70mm to 75mm total before you reduce GPU clearance significantly. In the North XL, top thickness can be around 65mm to 70mm total, and front can handle 85mm or more if you have a shorter GPU under 300mm. For custom loops with 45mm or 60mm thick radiators, plan to front mount and use slim fans if needed.
Will a front radiator affect my GPU length?
Yes, but only slightly with a slim radiator. The standard North allows up to 355mm for GPUs with front fans only. Add a typical 27mm radiator and 25mm fans, and you lose about 52mm, leaving roughly 303mm for the GPU. Many RTX 4070 and 4080 cards at 304mm to 340mm will still fit, but cards over 340mm may require a 240mm radiator or a thinner setup. The North XL starts with up to 380mm GPU length, so even with a 52mm stack you still have about 328mm, which fits most large cards. Always measure your specific card length including the power connector.
