Printf String Formatter
Preview printf-style templates with JSON arguments, numeric bases, decimal precision, field padding and a per-argument breakdown.
Ready. Explore the example or use the input controls to begin.
Scope and practical limits
Supported placeholders: %s, %d, %i, %f, %x, %X, %o, %b and %%. Flags -, + and 0 are supported. No positional parameters or dynamic widths. Up to 500 arguments.
The tool processes your work in the browser. The website’s advertising and analytics follow its privacy and consent settings. Projects are not saved automatically. Media workspaces export their files directly rather than storing them in project JSON.
Using Printf String Formatter
A limited formatter for testing templates, not a C runtime. Integers must be safe JavaScript numbers.
- Start with the included example, or enter your own input.
- Adjust the settings and review the preview and any validation message.
- Download the result or save a project to continue later.
Example
Try Total: %08.2f with [12.5] to produce Total: 00012.50.
Questions & answers
Does this execute code?
No. The formatter parses supported placeholders and reads JSON values; it does not evaluate code.
Is my project saved automatically?
No. Use Save project to keep an editable copy. Processing runs in the browser; site ads and analytics follow the website privacy and consent settings.
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