Free tool
Base64 Size Estimator
Estimate decoded file size from Base64 strings.
Data URLsInstantNo uploads
Why it helps
Quick estimates
Check Base64 payload size before shipping.
Works with data URLs
Paste raw Base64 or a full data URL.
Base64
Base64 size estimator
Data URLs
Bytes
0
KB
0.00
MB
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FAQ
Quick answers about this tool.
Is this private?
Yes. All processing happens in your browser.
Do I need an account?
No. These tools are free and work without signup.
Can I use multiple files?
Yes. Most tools support batch processing.