CONVERT GSM → W64 (GSM to W64)
Fast, secure GSM to W64 conversion. No registration required.
📈 Target Minimum File Size (Guaranteed ≥ KB)
Lossless JPEG Q100 + standard COM segment padding for government & exam portals
Tap to choose your file Drop files here or click to browse
Automatic format identification and lossless transcoding across 201+ formats.
Convert to:
Detecting available formats...
Target Max File Size:
Uploading...
Processing your file...
READY!
Download File
Your file is converted & verified! Unlock instant download:
One-time secure payment via Stripe (Apple Pay, Google Pay, Card). Zero recurring subscription.
🛡️ Verification Audit
- ✓
- ✓ sRGB Color Fidelity
- ✓
Continue with this converted file (0s zero re-upload):
Batch Conversion Ready!
Your file is converted & verified! Unlock instant download:
One-time secure payment via Stripe (Apple Pay, Google Pay, Card). Zero recurring subscription.
Need to convert larger files or bigger batches right now?
Unlock up to 1 GB & priority cloud queue with 1-click Stripe checkout (Apple Pay, Google Pay, Card):
HOW TO CONVERT GSM → W64
Upload the GSM
Drop or select your GSM file. The upload is encrypted and the file is queued for conversion.
Transcode via FFmpeg
FFmpeg decodes the GSM stream to PCM internally, then re-encodes as W64 at the bitrate you select.
Download the W64
The W64 is delivered as a direct download; metadata and cover art transfer automatically where possible.
Why this pair exists — GSM is an audio format with specific trade-offs between file size, bitrate flexibility, and device support. Ergo, the W64 route. Need a W64 version of a GSM recording for a podcast host, audio book platform or DAW that refuses the original container? Drop the file above and our encoder produces a clean W64 you can drag straight into the destination tool. Metadata such as title, artist and cover art travels with the audio. Technical note: GSM is an audio format with specific trade-offs between file size, bitrate flexibility, and device support. Compare that with W64 is an audio format with specific trade-offs between file size, bitrate flexibility, and device support.
Why convert GSM to W64
GSM Audio is great in its own niche, but Sony Wave64 is either more universally playable or better suited to the device you are targeting. Converting lets you ship the audio without asking listeners to install a codec. The loss in quality between the two is negligible at sensible bitrates.
GSM vs W64 — Technical specifications
Side-by-side comparison of the technical details.
GSM
- MIME type
- audio/gsm
- Extension
- .gsm
- Codec
- GSM 06.10 (RPE-LTP)
- Sample rate
- 8 kHz
- Bitrate
- 13 kbps
- MIME Type
- audio/gsm
- Category
- Audio Files
- Full Name
- GSM Audio
- Conversion Engine
- FFMPEG
W64
- MIME type
- audio/x-w64
- Extension
- .w64
- MIME Type
- audio/x-w64
- Category
- Audio Files
- Full Name
- Sony Wave64
- Conversion Engine
- FFMPEG
- Max size
- 2^64 bytes
- Relative
- RF64 (EBU 64-bit WAV)
| Specification | GSM | W64 |
|---|---|---|
| MIME type | audio/gsm | audio/x-w64 |
| Extension | .gsm | .w64 |
| Codec | GSM 06.10 (RPE-LTP) | — |
| Sample rate | 8 kHz | — |
| Bitrate | 13 kbps | — |
| MIME Type | audio/gsm | audio/x-w64 |
| Category | Audio Files | Audio Files |
| Full Name | GSM Audio | Sony Wave64 |
| Conversion Engine | FFMPEG | FFMPEG |
| Max size | — | 2^64 bytes |
| Relative | — | RF64 (EBU 64-bit WAV) |
GSM vs W64 — Strengths and limitations
What each format does best, and where it falls short.
GSM Strengths
- Tiny bitrate (13 kbps) — hours of speech in a few MB.
- Speech-optimized — clear voice reproduction.
- Universal cellphone decoder adoption 1991-2015.
- Stable since 1987.
Limitations
- Speech-only — music sounds distorted.
- 8 kHz sampling — narrowband, muffled by modern standards.
- Legacy — LTE VoLTE moved to AMR-WB, Opus, or EVS.
W64 Strengths
- Unlimited file size (64-bit chunks).
- Professional DAW compatibility.
- Bit-exact lossless.
Limitations
- Less universal than WAV.
- Niche — only matters for very large sessions.
- Competes with RF64.
Quality & Compatibility
Lossy-to-lossy transcoding (most cross-format audio jobs) loses a tiny amount of quality on each pass — usually inaudible at our default VBR ~190 kbps for music or 96 kbps for speech. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy is only as good as the target bitrate you choose.
Tips for Best Results
- Pick 128 kbps for podcasts and voice, 192–256 kbps for music, 320 kbps only if the audio will be edited further downstream.
- Keep the GSM master alongside the W64 — re-encoding a lossy format twice accumulates audible artefacts.
- For mono voice content, convert to mono W64 explicitly to halve file size without any quality loss.
Frequently Asked Questions
Lossy-to-lossy conversions (most combinations) re-compress the audio, which technically introduces some loss. At a 192 kbps or higher target it is inaudible on normal equipment. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy transcodes are only as good as the target bitrate you choose.
For voice content (podcasts, audiobooks, lectures) 128 kbps is indistinguishable from higher bitrates. For music, 192-256 kbps covers most listening; 320 kbps is the ceiling for W64 and the right choice for audio you plan to edit further. Above that, prefer a lossless target instead.
Yes. Title, artist, album, year and cover art travel from the GSM container to the W64 container automatically where both formats support them. If a tag field has no W64 equivalent, it is dropped silently. Use any tag editor (Mp3tag, MusicBrainz Picard) to fine-tune afterwards.
GSM Audio
Source formatGSM 06.10 is a speech compression standard designed for the Global System for Mobile Communications. It encodes speech at 13 kbps using Regular Pulse Excitation with Long Term Prediction, optimized for voice intelligibility over cellular networks.
Sony Wave64
Target formatWave64 (W64) is an extension of the WAV format developed by Sony that breaks the 4 GB file size limit of standard WAV by using 64-bit chunk sizes. It is used in professional audio production for very long or multi-channel recordings.
Going the other way? Convert W64 back to GSM with the same engine.
Common Use Cases
Share across platforms
Send W64 files to anyone without worrying about whether they have the right software for GSM.
Embed in documents
Drop W64 output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
W64 often produces smaller files than GSM for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
GSM vs W64 — Typical file sizes
Approximate file sizes for common scenarios.
- 1 min of voice ~100 KB
- 1 hour voicemail archive ~6 MB
- 1-hour 24-bit 48 kHz mono ~620 MB
- 48-hour field recording ~30 GB
Need to Convert Gigabyte Archives or Mass Folders?
KaijuConverter delivers ultra-fast in-memory conversions for everyday tasks. For multi-gigabyte production workloads without browser bandwidth bottlenecks, explore high-throughput desktop suites.
One-time payment with zero recurring commitment: convert files up to 1 GB, OCR, PDF/A, and .ZIP batches for 24 hours.
Full 7 days of unlimited conversions, up to 2 GB per file, 100% ad-free with zero subscription.
High-throughput enterprise pipeline for files up to 2,048 MB, 50-file batches, ISO PDF/A, and priority processing.
Convert thousands of camera RAW files (CR3, NEF, ARW) to WebP, AVIF, or TIFF in one pass.
GPU-accelerated RAW development with end-to-end 16-bit ICC color profile management.
Related comparisons
See these formats side by side to understand which fits your use case best.
</>
Embed this tool on your website or blog (Free)
▼
Add this converter to your site in 10 seconds
Help your visitors convert files directly from your documentation, CMS, or blog. Copy the lightweight HTML snippet below — zero dependencies, responsive, and 100% free.
Secure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.