The 7 Best USB To CAN Adapters
Updated by · How we research
Seven USB-to-CAN adapters compared on CAN FD support, isolation and software, from open boards to PEAK interfaces. Our pick: the Grid Connect GC-CAN-USB-ISO. When users buy our independently chosen editorial recommendations, we may earn commissions to help fund the Wiki.
Newer car controllers and robot motor drives increasingly talk CAN FD, a faster version of the CAN bus that many popular adapters can't read at all. Check your network before you buy. These USB dongles let a laptop watch, log and send traffic on a vehicle or machine network, and this list covers engineers, technicians and hobbyists, from shop benches to robot builds.
Editor's Notes
October 23, 2026, by Ezvid Wiki Admin:
The new top pick, the Grid Connect GC-CAN-USB-ISO, turns out to be PEAK-System's isolated PCAN-USB under a reseller's label, and the Grid Connect PCAN-USB Pro FD is PEAK hardware too. PEAK's drivers and free tools are what most CAN software expects, so that's where the list starts.
Cheap boards built on the open CANable design have changed this category, so the DSD TECH SH-C31A, the Jhoinrch RH-02 Pro and the Pibiger SavvyCAN-FD-C join, along with the two-port Waveshare USB-CAN-FD. Kvaser now lists the Kvaser Leaf Light v2 as end of life; it stays for shops already running Kvaser software.
The Utek UT-8251, ViewTool VTG203B and Innomaker module are no longer sold, and Kvaser has retired the Leaf Pro HS v2. The Drew Tech Mongoose Pro is gone as well, and it was a pass-thru reflashing tool rather than a plain adapter. Nobody publishes lab tests of these dongles, so we leaned on PEAK and Kvaser data sheets, the open firmware projects, the Linux kernel's CAN documentation and a long engineers' forum thread.
February 23, 2021:
To reiterate the previous editor’s note, these devices are used in a fairly specialized context, and there aren’t a whole lot of manufacturers on the market, so, by extension, there is a limited number of decent models. With that being said, I’ve left all of the models in from the previous update, as they’re all still decent, and I could find few others without issues that made me even want to consider including them on our list. I have however added the Grid Connect Pro FD, which supports the CAN FD or (CAN Flexible Data-Rate) protocol that builds on classical CAN. Although Grid Connect does have its own models, I do believe that they’re also a distributor or reseller of many of the adapters and other hardware components from Peak View, which is not necessarily a bad thing, because Peak View makes some of the best adapters and hardware interfaces for CAN.
Since CAN is a data bus, like USB, and not an actual hardware interface, it can use a variety of different connector types, which is why we’ve included options like the Drew Tech Mongoose Pro for OBD-2 ports, as well as the Utek UT-8251 ; many systems, however, will employ a 9-pin, d-subminiature connector, or a DE-9. Likewise, not all DE-9-to-USB adapters won’t meet the requirements needed to support or facilitate high-speed CAN connections. Quickly on the note of connectors, the DE-9 connector is often mislabeled and sold as a DB-9 connector, which is a mistake that stems from the fact that DB-25 connectors were replaced with DE-9 connectors on laptops, and most sellers simply carried the ‘B’ over without thinking twice about what it represented – which is the shell size, and should be represented with an ‘E’ in the case of the 9-pin d-sub. Unfortunately, the ‘B’ is still used, so don’t be confused.
June 07, 2019:
These devices are often used in a very specialized context and their descriptions involve a lot of jargon, so let's break down some of the main features so you can better understand which interface is best suited for you.
First let's talk data throughput speed. Data travels across CAN networks in packages called messages, of which frames are the most common. Some manufacturers use frames to measure the speed of their interfaces, such as the ViewTool VTG203B, which moves data at 8,000 frames per second. Others are measured using bits, like the Grid Connect GC-CAN-USB-ISO, rated at 1 megabit per second. A more technical term for this is the baud rate.
Messages can be different data sizes, depending on the CAN protocol. CAN2.0A and CAN2.0B are the most common, with 11-bit and 29-bit messages, respectively. Models like the Utek UT-8251 work with both, and this something that should be taken into careful consideration before making a purchase.
Special Honors
Kvaser Leaf v3 And U100 Kvaser's replacement for the Leaf Light v2 is the Leaf v3, and its U100 is a rugged single-channel CAN FD interface with reinforced isolation. Both are sold through Kvaser and its distributors, and they use the same free CanKing software and drivers. kvaser.com
PEAK-System PCAN-USB FD PEAK's single-channel CAN FD adapter sits between its classic PCAN-USB and the two-channel Pro FD. It handles data bit rates up to 12 Mbit/s, has isolation up to 500 volts and one-microsecond timestamps, and runs the same drivers and PCAN-View monitor. peak-system.com
Classic CAN Or CAN FD
Two channels let you watch both sides of a gateway, or bridge two networks, which is why the two-channel PEAK and Waveshare boxes exist.
Classic CAN (CAN 2.0A and 2.0B) carries up to 8 data bytes per frame at up to 1 Mbit/s, and most cars still run their main networks at 500 kbit/s. That's all the PEAK PCAN-USB and the Kvaser Leaf Light v2 handle. CAN FD keeps the same wiring but sends up to 64 data bytes per frame and speeds up the data phase; PEAK rates its PCAN-USB FD for data bit rates up to 12 Mbit/s.
A classic-only adapter can't decode FD frames, and on a mixed bus it sees them as errors. If you work on newer vehicles, motor controllers or robotics gear, check the controller's data sheet first. If the bus is classic and always will be, an FD adapter costs little extra but buys nothing.
Channel count is the other split. One channel covers almost every job. Two channels let you watch both sides of a gateway, or bridge two networks, which is why the two-channel PEAK and Waveshare boxes exist.
Isolation, Termination And Wiring Traps
Galvanic isolation separates the adapter's bus side from your laptop's ground. On a running vehicle or an industrial machine, the two grounds can sit at different voltages, and a fault can travel up the USB cable. PEAK sells the PCAN-USB with or without isolation (up to 500 V on the IPEH-002022 version, per PEAK), while Kvaser builds isolation into the Leaf Light v2. Budget boards vary: some isolate, many don't. Isolation protects the computer, not the bus, so it won't save the car from a wiring mistake.
A CAN bus needs a 120-ohm resistor at each of its two ends and nowhere else. A bench setup with just the adapter and one module usually needs the adapter's resistor switched on; a car's network already has its own. Missing termination, the wrong bit rate and swapped CAN high and low wires cause most "it doesn't work" reports. PEAK's adapters set termination and an optional 5 V supply on pin 1 with solder jumpers, according to PEAK's specifications.
Reading a car's bus through the OBD-II port is common and fairly safe. Sending frames into a live vehicle is not: brakes, airbags and steering can share that network. Reflashing an engine computer is a job for a J2534 pass-thru tool and the automaker's software, not a plain CAN adapter. Grid Connect's setup guide walks through a first connection.
Software Is What You're Paying For
The hardware inside a cheap board and a professional dongle is not so different; the software is. PEAK ships PCAN-View and the PCAN-Basic programming library, and Kvaser ships CanKing and its CANlib library, with drivers for Windows and Linux. Commercial tools and lab software generally support both brands out of the box.
Budget boards based on the CANable design run open firmware. With candleLight firmware they appear on Linux as a native SocketCAN port (see the kernel's CAN documentation), and you bring them up like a network card. The free SavvyCAN program and python-can, which supports PEAK, Kvaser, candleLight and serial-line (slcan) adapters, cover logging, replay and scripting. On Windows, expect more setup.
Serial-line firmware is simpler but slower. Engineers in a long EEVblog thread note that serial-type adapters can choke on busy buses, while PEAK and Kvaser dongles run for years without fuss. If you need to log a heavily loaded network or hand scripts to coworkers, the pro drivers earn their price.
How we researched this
We compared 17 USB-to-CAN adapters, read the PEAK-System and Kvaser data sheets, the open-source firmware and Linux kernel documentation that budget boards depend on, and a long engineers' forum thread, looked at owner feedback patterns, and checked every brand for recalls with the U.S. Consumer Product Safety Commission.
Frequently asked questions
What is a CAN bus?
It's a two-wire network that lets the controllers in a car, truck, boat or machine share messages. Each module can talk and listen on the same pair of wires, and a USB-to-CAN adapter lets a computer join in.
Do I need a CAN FD adapter?
Only if your network uses CAN FD, which is common in newer vehicles, motor drives and robotics. A CAN FD adapter also reads classic CAN, but a classic-only adapter can't read CAN FD frames.
Do I need galvanic isolation?
It's worth having whenever the bus belongs to a vehicle or machine with its own power supply, because the grounds may not match your laptop's. On a bench with a USB-powered board, a non-isolated adapter is usually fine.
Is the Grid Connect adapter the same as a PEAK PCAN-USB?
Yes. Grid Connect resells PEAK-System's PCAN-USB, PCAN-USB opto-decoupled and PCAN-USB Pro FD, and the hardware carries PEAK branding. It uses PEAK's drivers and software.
Can a USB-to-CAN adapter reflash my car's computer?
Not by itself. Shops use a J2534 pass-thru tool with the automaker's software for that. Holley EFI owners should use Holley's own CAN-to-USB cable, which works with Holley's tuning software.
Do the cheap adapters work on Windows?
Yes, with tools such as Cangaroo, SavvyCAN or python-can, but setup takes more steps than on Linux, where candleLight-based boards show up as native CAN ports.
