What is the V file format?
.v is the standard source file extension for Verilog, a hardware description language (HDL) used to model digital circuits for FPGA programming and ASIC design. Verilog was created in 1984 by Phil Moorby and Prabhu Goel at Gateway Design Automation and was later standardized as IEEE 1364-1995. It allows engineers to describe hardware behavior, structure, and timing at register-transfer level (RTL), which synthesis tools then map to actual logic gates.
A .v file contains one or more module definitions. Each module declares its port list, internal wire and reg signals, parameters, and logic expressed through always blocks (behavioral), assign statements (combinational), or structural instantiation of other modules. The file version - Verilog-95, Verilog-2001, or Verilog-2005 - is not declared in the file; tools infer it from the syntax constructs used.
Verilog-2005 (IEEE 1364-2005) was the last standalone standard before SystemVerilog (IEEE 1800-2017, .sv) merged HDL with hardware verification language features, making it the modern successor. .v files remain heavily used in legacy FPGA and ASIC projects worldwide. VHDL (.vhd) is the main alternative HDL, prevalent in defense and European aerospace contexts.
Simulation tools such as iverilog (Icarus Verilog) and Verilator, and synthesis tools such as Vivado (AMD/Xilinx) and Quartus Prime (Intel/Altera), all accept .v files natively.
Security & safety
RISK: LOWPlain text source code; no execution risk when viewed in a text editor. Risk only when synthesized and programmed onto hardware - review RTL from untrusted sources for hardware Trojans.
Format details
in a nutshell- V language source file - The V programming language (vlang.io, 2019) also uses .v extension for its source files - unrelated to hardware design.
- Coq / proof assistant file - Coq proof assistant occasionally uses .v for theorem proof scripts; distinct from Verilog.
Programs that open V files
Windows6 apps
Vivado Design Suite (AMD/Xilinx)
Freemium Create or open a project, add .v files as design sources; synthesis and simulation built-in.
Quartus Prime (Intel/Altera)
Freemium Add .v files to a Quartus project; synthesize and simulate for Intel FPGAs.
ModelSim / Questa (Siemens EDA)
Freemium vlog file.v to compile; vsim module_name to simulate in waveform viewer.
Visual Studio Code + TerosHDL extension
Open-source Open .v files with syntax highlighting, linting, waveform viewer integration.
ISE Design Suite (Xilinx)
Free Legacy tool for pre-7-series FPGAs (Spartan-6, Virtex-6); last version 14.7 (2013). Replaced by Vivado for newer devices.
VeriLogger Extreme (SynaptiCAD)
Paid Verilog/SystemVerilog simulator; site may be outdated - verify before recommending. 
macOS1 app
Icarus Verilog (iverilog)
Open-source Install via Homebrew: brew install icarus-verilog; then iverilog -o sim file.v 
Linux4 apps
Icarus Verilog (iverilog)
Open-source iverilog -o sim file.v && vvp sim - compiles and simulates; GTKWave for waveforms.
Verilator
Open-source verilator --cc file.v - compiles Verilog to fast C++ simulation model; industry-grade open-source simulator.
Vivado Design Suite
Freemium vivado project mode or non-project mode for synthesis/simulation on Linux. Technical details
deep spec| Language standard | IEEE 1364-1995, 1364-2001, 1364-2005 (Verilog-2005) |
| Successor standard | SystemVerilog IEEE 1800-2017 (`.sv` extension) |
| Encoding | ASCII (per IEEE spec); tool-dependent Unicode support in comments |
| Top-level construct | `module ... endmodule` block |
| Simulation constructs | `always`, `initial`, `#delay`, `$display`, `$monitor`, `$dumpvars` |
| Synthesis constructs | `always @(posedge clk)`, `assign`, structural module instantiation |
| Logic value system | Four-valued - 0, 1, X (undefined), Z (high-impedance) |
| Typical file size | 500 B - 500 KB per module; synthesized netlists up to several MB |
| Version detection | No in-file version declaration - tools infer version from syntax constructs used |
| Open-source simulation | Icarus Verilog (`iverilog`), Verilator |
| Commercial synthesis tools | Vivado (AMD/Xilinx), Quartus Prime (Intel/Altera) |
| MIME type | `text/plain` (also `text/x-verilog` informally) |
| Released | 1984 (Verilog language); IEEE 1364-1995 standard |
| Latest version | Verilog-2005 (IEEE 1364-2005); superseded by SystemVerilog (IEEE 1800-2017) |
| Open standard | Yes · royalty-free |
| Specification | ieeexplore.ieee.org |
V conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about V files.
