SPICE simulators compared: free, online and desktop options
SPICE simulators compute the voltages and currents in an analog (or mixed-signal) circuit from models of its real components. Free desktop options: Analog Devices' LTspice (Windows and macOS, schematic and waveform viewer), the open-source ngspice (command line, and the engine inside KiCad's simulator), Sandia's Xyce (built for very large, parallel simulations), Qucs-S (a free schematic front end for ngspice, Xyce and others), Texas Instruments' no-cost PSpice for TI and TINA-TI, and Micro-Cap 12, now a free download. Paid: NI Multisim (subscription or perpetual licenses), which also has Multisim Live online. In the browser: CircuitLab (memberships from $24 a year), Multisim Live and EasyEDA's simple simulation; PartSim, a former free online option, shut down on January 1, 2023. For SPICE, the choice depends on your platform, your parts library and whether you need a browser. For digital logic, a switch-level simulator is simpler.
How to choose a SPICE simulator
Most hobbyists and students start with LTspice on Windows or macOS. On Linux, Qucs-S over ngspice, or KiCad's simulator if you are also laying out a PCB. For TI parts, PSpice for TI or TINA-TI. For very large simulations, Xyce. In a browser, CircuitLab or Multisim Live. Older but free: Micro-Cap 12. (digiwleea is an independent project, not affiliated with any of these tools.)
Where digiwleea fits
digiwleea is not a SPICE simulator. It simulates digital logic at the switch level: every wire is 0, 1 or floating, and transistors are ideal switches. That makes it fast to understand and enough to build a computer: you wire NMOS and PMOS transistors into NOT and NAND, then build adders, latches, registers, RAM and an 8-bit CPU that runs a stored program, in the browser, through a 40+ level course where every part is checked against its truth table, with an AI tutor (Wleea). Use a SPICE tool for analog behaviour such as voltages, timing and power; use digiwleea to learn how logic and computers work.
SPICE simulators side by side
| Runs on | Price | |
|---|---|---|
| LTspice | Windows, macOS | Free |
| ngspice | Windows, Linux, FreeBSD, macOS (command line) | Free, open source |
| Xyce | Desktop platforms; parallel on Unix-like systems | Free, open source |
| Qucs-S | Linux, Windows, macOS (front end for ngspice, Xyce) | Free, open source |
| KiCad | Cross-platform (simulation through ngspice) | Free, open source |
| PSpice for TI | Desktop installation, works offline | No cost (TI edition) |
| TINA-TI | Desktop download (about 500 MB) | No cost (TI edition) |
| Micro-Cap 12 | Windows | Free download |
| Multisim | Windows; Multisim Live online | Paid licenses; Multisim Live can be tried free |
| CircuitLab | Browser | Memberships from $24 a year |
| EasyEDA | Browser or desktop client | Free (simple simulation) |
For browser simulators beyond SPICE, see free circuit simulators online.
No sign-up is needed to start: open the lab and place your first transistor, or read the free theory course. The account (and the AI tutor) are optional.
More comparisons: Electronics and SPICE simulators
See for yourself: build a logic gate from transistors in the simulator, then follow the path from sand to an 8-bit CPU.
Open the digiwleea lab →Frequently asked
What is the best free SPICE simulator?
LTspice is the usual starting point on Windows and macOS. ngspice is the main open-source engine, used by KiCad and Qucs-S, and Xyce handles very large simulations. TI's PSpice for TI and TINA-TI are no-cost editions.
Is there an online SPICE simulator?
Yes. CircuitLab runs in the browser with paid memberships, Multisim Live is NI's online version, and EasyEDA includes simple simulation. PartSim, a former free option, shut down on January 1, 2023.
Do I need SPICE to learn digital logic?
No. A switch-level logic simulator shows 0s and 1s directly and is simpler for gates, flip-flops and CPUs. SPICE matters when you need voltages, currents, timing or power.