When you’re on a budget but still want your tracks to sound polished and pro-level, it is time to check out some of these best free mastering VST plugins to get you going.
Well, you know that mastering can feel like wizardry. You slap a limiter on, maybe tweak an EQ, add some compression, and hope for the best. And the thing is, every time, the right tools are the key to making a difference.
Well, you’ll be happy to know that it doesn’t take hundreds of dollars to get great results. Some of these free mastering plugins can stand toe-to-toe with paid ones, and in the right hands, they work wonders.
So, whether you’re finalizing your first mixtape, cleaning up a podcast, or just curious about what’s out there, I’ve got you covered. I’ve tested a ton of free mastering plugins (because, well… I have a bit of a plugin addiction), and I’m here to share the absolute best ones you can grab in 2025.
Some are clean and transparent, others add color and warmth, but they all have one thing in common: they sound fantastic. Let’s start!
1. Analog Obsession OAQ
My first pick is the OAQ, which shines with its perfect sweet spot between flexibility and ease of use.
A lot of mastering EQs either give you too much freedom (hello, option overload) or keep things too simple, but OAQ lands right in the middle. The interface is clean, resizable, and intuitive, which is always a plus, especially when beginners considered.
- 6-Band EQ with Selectable Frequencies
I love how each band has carefully chosen frequency points, making it super easy to dial in adjustments without getting lost in endless numbers. It’s like having a curated set of tone-shaping tools that always sound musical.
- Mid-Side & Dual-Mono Processing
This is where OAQ really shines for me. The ability to shape the mid and side channels separately lets me widen mixes in a way that feels natural, not forced.
- Drive with x4 Oversampling
This isn’t just a clean digital EQ, as it can get warm and rich with the Drive knob engaged. And the oversampling ensures that even with heavy saturation, it stays smooth and controlled.
My only gripe? The resizing can be a bit finicky, especially if you’re loading new instances. But once you set it up properly, it remembers your settings, so it’s more of a minor quirk than a dealbreaker.
Overall, OAQ is one of those free plugins that feels premium, and it’s found a permanent spot in my mastering chain.
OAQ comes in VST3 and AAX for Windows and AU, VST3, and AAX for Mac.
2. SlateDigital FreshAir
If you’ve ever struggled to get that silky, open high-end in your mix without introducing harshness, Fresh Air, another great free mastering vst, may be your new best friend, as it’s like an instant “clarity button” for your vocals, drums, and mix bus.
What I love about Fresh Air is how effortlessly it brings life to a mix. Some exciters can be too aggressive, adding an artificial-sounding boost, but this one feels smooth and natural.
It reminds me of the Waves Aphex Exciter, but with a more refined touch that works especially well on vocals and acoustic instruments and without any cost.
- Mid Air & High Air Processing
These two controls let me lift a vocal or mix without making it brittle. Mid Air enhances clarity, while High Air opens up the top end beautifully.
- Dynamic High-Frequency Processing
Unlike a basic exciter, Fresh Air adapts to the input, making it feel natural rather than overcooked. I love using this on drum buses to add brightness without making cymbals too sharp.
- Fast & Intuitive Workflow
It’s one of those plugins that sounds great in seconds. No deep tweaking, just turn the knobs and get an instant polish.
If you’re connected and need a quick, effortless way to add shimmer to your mix, Fresh Air is a no-brainer.
Fresh Air is available in VST3, AU, and AAX formats for Windows and Mac.
3. iZotope Ozone Mastering EQ
I never thought I’d see the day when iZotope (well, now Native Instruments, actually, but still) gave away a standalone Ozone EQ for free, but here we are! Ozone 11 Equalizer, a fully functional EQ packed with practical, mix-enhancing tools, is offered for free by NI.
As one of the most popular free mastering plugins, Ozone 11 EQ doesn’t just feel like another generic equalizer as it adds real utility to your workflow. It’s got a clean, intuitive interface, and the workflow is smooth, making it easy to dial in precise adjustments without second-guessing your ears.
- Transient/Sustain Processing Mode
This feature is a game-changer for mastering. Instead of just adjusting static EQ bands, I can separately shape the transient and sustain of a sound, letting me add punch to a kick drum without affecting its body.
- Delta Function for Precise Adjustments
Ever made an EQ tweak and wondered what you actually changed? The Delta button lets me hear only the difference between the original and processed signal, so I know exactly what’s happening.
- Mid/Side & Analog/Digital Modes
Whether I want surgical digital precision or a more natural, analog-style tone, this EQ handles both beautifully. The Mid/Side processing is a bonus for stereo shaping and is perfect for adding width without affecting the mono core.
There’s no iLok required, which is a breath of fresh air, but you do need Native Access to install it. If you’re not a fan of Native Instruments’ ecosystem, that could be a minor hassle.
That said, a free mastering-grade EQ from iZotope? This one’s an absolute steal and it’s staying in my toolbox.
Ozone 11 Equalizer is available in VST3, AU, and AAX formats for Windows and macOS.
4. bx_masterdesk Classic
bx_masterdesk Classic mastering plugin distills a full analog mastering chain into an easy-to-use, three-step workflow, making it a perfect choice for quick, professional-sounding results.
I think bx_masterdesk Classic can’t be a replacement for dedicated mastering tools, but for a fast, polished master without the hassle, it’s a gem, especially at the unbeatable price of free.
For me, the highlight here is that this free mastering VST excels at keeping things minimal yet effective. Instead of overwhelming you with endless parameters, it guides you toward a balanced master with just a few well-designed controls.
- Volume, Foundation, and Tone Controls
Instead of traditional EQ and compression settings, bx_masterdesk Classic simplifies the process with three core dials. Adjusting these instantly shapes the mix without needing deep technical knowledge.
- Analog Mastering Chain with TMT Processing
The analog-modeled processing gives mixes a rich, cohesive sound, while Brainworx’s Tolerance Modeling Technology (TMT) subtly emulates real hardware variations, adding an organic feel.
- Built-in Stereo Enhancement & Saturation
When I need extra width or warmth, the stereo enhancer and THD (Total Harmonic Distortion) controls get the job done without overcooking the sound, though it’s easy to go overboard if you’re not careful.
While it lacks deep customization, bx_masterdesk Classic is designed for speed and efficiency. The preset system is a lifesaver for getting quick ballpark settings, and for many projects, that’s all you really need.
For a free, no-fuss mastering solution, this is a great vst mastering unit is one of the best I’ve tried. If you haven’t grabbed it yet, it’s worth a download.
bx_masterdesk Classic is available in VST, VST3, AU, and AAX formats for Windows and macOS.
5. ZL Equalizer
I always enjoyed seeing free dynamic EQs that actually compete with premium plugins, and ZL Equalizer is a serious contender.
With its 16-band dynamic EQ and advanced filter types, stereo modes, and flexible slopes, it is one of the most feature-rich free EQs I’ve come across. If you’ve ever wanted an open-source alternative to FabFilter Pro-Q, this might be the closest thing yet.
What makes ZL Equalizer special is its precision and flexibility. Whether I’m using it to tame harsh frequencies like Soothe, create space like TrackSpacer, or shape dynamics in a mix, it delivers clean, musical results with low CPU usage.
- 16 Dynamic EQ Bands with 8 Filter Types
This gives me surgical control over my sound, whether I need to notch out resonances or add movement to specific frequency ranges.
- 5 Stereo Modes & Sidechain Support
I appreciate being able to process the mid and side channels separately or even use external sidechain signals to carve space between elements in a mix.
- Interactive Spectrum & Smart Collision Detection
The real-time visual feedback makes it easy to spot clashing frequencies and apply corrections without second-guessing.
For a completely free dynamic EQ, ZL Equalizer is one of the best free EQs out there, and it’s worth grabbing if you’re looking for a serious tone-shaping tool without the price tag.
ZL Equalizer is available in VST3 and AU formats for Windows, macOS, and Linux.
6. Lotus Sounds LS-1173
If you’re after that warm, punchy API-style EQ but don’t want to shell out for the Waves or UAD versions, LS-1173 is a great option to check out.
This analog-inspired EQ and preamp plugin brings some serious vintage character to the table, giving your mixes that classic 500-series tone with a simple, no-fuss interface.
The 3-band EQ of LS-1173 is straightforward and musical, while the preamp drive adds saturation and warmth that can push tracks forward in a mix. It’s a great tool for adding color, to vocals, drums, or a mix bus.
- API-Style 3-Band EQ
Each band is carefully tuned, making it easy to enhance frequencies in a musical way without overthinking settings. It’s great for broad tone-shaping.
- Analog-Modeled Preamp Drive
When I want a little extra grit and warmth, the preamp drive adds just the right amount of harmonic richness without sounding harsh.
- Lightweight & Easy to Use
At just 12.7MB on Mac and 4.5MB on Windows, this plugin loads instantly and doesn’t hog CPU, making it a great option for stacking on multiple tracks.
The only downside is that Mac users might run into issues with unsigned plugins, which can be a hassle to work around. But once it’s up and running, it’s a solid, free alternative to pricey API emulations.
LS-1173 is available in VST3 and AU formats for Windows and macOS.
7. Platone Studio Alton Limiter
Alton Limiter hits a nice balance, as it’s simple, clean, and does exactly what you need it to do: control peaks and boost loudness without wrecking your mix.
When it comes to free limiters, most fall into two categories: they’re either too barebones to be useful or packed with features that make them harder to use than they should be, while Alton Limiter has feet on both sides.
What I like about this free vst mastering suite is that it doesn’t try to be overly complex. It’s designed for fast, transparent limiting, but can also add a bit of character if you push it.
The stereo processing options give it some extra flexibility, and the real-time visual feedback makes it easy to dial in the right settings without guessing.
- Threshold & Release for Flexible Response,
For me, adjusting these two parameters is great for fine-tuning the sound whether I want a transparent, clean limiter or a slightly aggressive one that adds weight.
- Stereo & Dual-Channel Limiting
The ability to limit both channels together or separately makes it useful for wide mixes where I need to keep dynamics under control without crushing the stereo field.
- Low CPU Usage & Zero Latency
This thing runs super light, making it a great option for tracking, especially since there’s no noticeable latency even when used live.
My only nitpick? The interface is very blue (yes, I’m picky) ) it could use a bit more contrast to make the labels stand out in a busy DAW. Also, you can’t link the sliders, which might be a minor workflow issue for some users.
That said, for a free, easy-to-use limiter, Alton Limiter gets the job done quickly and efficiently and is definitely worth a spot in your plugin folder.
Alton Limiter is available in VST, VST3, and AU formats for Windows and macOS.
8. Variety of Sound ThrillseekerXTC
ThrillseekerXTC Mk III is a truly one of the best free mastering plugins out there. It brings depth, warmth, and attitude in a way that feels more analog than digital. Built around a parallel analog-style EQ, it enhances low, mid, and high frequencies separately, with a unique opto-compression circuit in the mid band to improve presence and glue.
The reason why I selected ThrillseekerXTC Mk III is because it goes beyond just boosting high frequencies. Instead, it recreates the warmth of transformer-coupled hardware, giving mixes that rich, analog saturation while keeping things musical.
It’s a great alternative to hardware-inspired exciters like Waves Aphex or SPL Vitalizer, but it’s completely free.
- Three Parallel Bands with Dedicated Processing
Unlike standard exciters, this one gives separate control over lows, mids, and highs, allowing me to add weight, warmth, and clarity without overcooking any part of the mix.
- Opto-Compression in the Mid Band
This gentle mid-band compression brings a smooth, glued-together feel that I love on vocals and mix buses. It enhances presence without making things harsh.
- Drive & Mojo for Analog Saturation
The Drive and Mojo controls now work as a dedicated output amplifier, adding vintage-style harmonic richness, ideal for warming up a sterile digital mix.
The new VST3 support makes it more accessible, but it’s still Windows-only, which might be a downside for Mac users. The small UI could also use an update, but for a free exciter that rivals paid plugins, I’m not complaining.
ThrillseekerXTC Mk III is available as a VST3 plugin for Windows.
9. TDR Kotelnikov
Most compressors either aim for vintage analog warmth or try to be as transparent as possible. Kotelnikov leans heavily toward the latter, and it does it incredibly well.
Designed for stereo bus compression, it controls dynamics precisely while keeping the original punch and tone intact. This isn’t an “analog-modeled” compressor; it’s proudly digital, built from the ground up for modern, high-fidelity compression.
In practice, Kotelnikov feels clean, natural, and almost invisible, as it’s one of those compressors that does a lot without sounding like it’s doing anything.
I often use it for different workflows like gluing a mix together, subtly taming transients, or controlling dynamics without coloration.
- Independent Peak & RMS Release Controls
This lets me fine-tune how the compressor reacts to transients vs. sustained sounds, making it perfect for maintaining clarity and impact in a mix.
- Delta Mode for A/B Comparisons
I like being able to solo the compressed signal and hear exactly what’s changing, which makes precise adjustments way easier than guessing.
- Advanced Stereo Linking & Sidechain HPF
The ability to adjust how the left and right channels interact means I can preserve the stereo image while still controlling dynamics effectively.
Kotelnikov is stealthy in the best way possible, as it lets you sculpt dynamics without adding weight, warmth, or color.
If you’re after a transparent, high-precision compressor that won’t interfere with your mix’s tone, this should be in your toolbox.
TDR Kotelnikov is available in VST, AU, and AAX formats for Windows and macOS.
10. Sampleson Overheat
I always tell myself I don’t need another saturator, and then one like OverHeat comes along and proves me wrong. This free analog saturation plugin delivers warm, harmonically rich distortion that can make sterile recordings feel alive.
What I love about this free mastering plugin is how effortless it is to dial in. It’s got a simple, no-fuss layout making adding subtle warmth or gritty, overdriven character easy.
- Tube-Style Harmonic Saturation
OverHeat emulates classic tube distortion, adding depth and weight to drums, vocals, and synths in a way that feels organic.
- Color & Low-Pass Filtering
The Color control subtly shapes the midrange, while the Low-Pass filter helps tame harshness when you push the saturation harder.
- Low CPU Usage & Simple Interface
Another plus for me is that I can run this on multiple tracks without worrying about my CPU, and the intuitive interface makes it easy to use in any mix.
One minor drawback is the lack of oversampling, which means aliasing could creep in at lower sample rates. But unless you’re cranking it aggressively, it’s not a major issue.
For a free mastering VST, OverHeat is a killer tool that is quick to set up, easy to use, and packed with analog-style warmth.
OverHeat is available in VST3 and AU formats for Windows and macOS.
11. Youlean Loudness Meter
Loudness can be tricky to get right, especially when streaming platforms, TV, and gaming all have different loudness standards. That’s where Youlean Loudness Meter 2 comes in as one of the best free mastering VSTs.
It’s one of the best free mastering plugins as a loudness meter, giving you accurate loudness readings without needing to spend a dime.
What I love about Youlean Loudness Meter 2 is that it’s not just for mixing and mastering, it’s also great for broadcast and game audio, thanks to its film, TV, and gaming presets.
Whether you need to hit Spotify’s LUFS target, avoid clipping on YouTube, or meet industry standards for TV, this plugin keeps your levels in check.
- Accurate Loudness & True Peak Readouts
With LU, INT, TP, LRA, PLR, and DR measurements, I can quickly check my mix’s dynamic range and make sure I’m not squashing the life out of my track.
- Custom True Peak Alert Threshold
This is a lifesaver for preventing digital clipping, especially when preparing mixes for streaming platforms or mastering engineers.
- Resizing, Scaling, and Mini View
The freely resizable GUI makes it easy to fit into any workflow, and the mini view keeps things compact when I don’t need a full-screen meter.
Even better, it runs light on CPU, supports mono, stereo, and 5.1 surround, and never expires, so once you grab it, it’s yours for good.
Youlean Loudness Meter 2 is available in VST2, VST3, AU, and AAX formats for Windows and macOS.
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12. Analog Obsession N492ME
If you’re after that rich, vintage Neumann console sound, this 4-band EQ from Analog Obsession is a must-try.
N492ME nails the smooth, resonant, low-end, and detailed presence that defined the 70s and 80s recording era, making it a nice tool for adding character to a mix.
The star here is the EQ, which adds great color, warmth, and musicality to the mix. The interface is well-designed, with clearly marked low, low-mid, high-mid, and high-frequency bands, plus Dual Mono, Stereo, and Mid/Side processing for extra flexibility.
- Neumann Console-Style Sound
The low end is tight and punchy, while the top end has a silky, open presence that never feels harsh.
- Dual Mono, Stereo & Mid/Side Modes
Being able to process the stereo field in different ways makes it super versatile for bus processing and mastering tweaks.
- Bypass Switches for Each Band
I liked that I could quickly A/B different adjustments, making it easier to hear what each frequency tweak is doing.
If you need precise, surgical EQ moves, this isn’t the tool for that.
But if you want a warm, character-driven EQ that enhances rather than corrects, this is a gem and the fact that it’s free makes it even better.
This plugin is available in VST3 and AAX for Windows and AU, VST3, and AAX for Mac.
13. Voxengo SPAN
If you’re serious about mixing, mastering, or audio analysis, SPAN is one of the best free spectrum analyzers out there cause it’s flexible, powerful, and customizable.
SPAN is an essential tool for understanding frequency balance, detecting problem areas, and ensuring proper loudness levels in a mix.
My admiration for SPAN comes from the fact that it’s not just a basic spectrum analyzer cause it offers detailed metering, multi-channel analysis, and customizable display settings.
When I’m checking for true peak clipping, analyzing mid/side content, or ensuring proper LUFS levels, it handles everything with precision and clarity.
- FFT Frequency Spectrum Analyzer
The real-time frequency display is clean, detailed, and customizable, making it easy to spot problem frequencies or fine-tune a mix.
- True Peak and Clipping Statistics
SPAN helps prevent distortion by providing true peak metering and clipping detection, which is crucial for mastering.
- EBU R128 & K-System Metering
Whether I’m mixing for streaming platforms, broadcast, or film, I can monitor loudness levels accurately and ensure compliance with industry standards.
With multi-channel analysis, stereo correlation metering, and customizable spectrum smoothing, SPAN is way more advanced than most free analyzers.
SPAN is available in VST, AU, and AAX formats for Windows and macOS.
Berk Öztuna, a musician from Istanbul, is skilled in handpan, percussion, and guitar, performing and recording his own compositions globally. With expertise in music production and audio technology, he integrates virtual instruments and sound design tools seamlessly into his work. He also writes insightful articles on music production and gear for platforms like Plugin Noise and shares his music on Spotify and Instagram.
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