Tool: Millisecond Converter

TLDR

• Simon Willison built a small browser tool to convert milliseconds into seconds and minutes after LLM prompt duration reporting caused repeated mental friction.

Key Takeaways

• LLM APIs and runtimes commonly report prompt durations in milliseconds, requiring manual conversion to more readable units.
• The tool was built to eliminate a recurring cognitive annoyance rather than as a planned product.
• Published April 24, 2026, and tagged as a utility tool in Willison’s Weblog.
• The project reflects a pattern of Willison shipping small, focused tools that solve specific personal workflow friction.

Why It Matters

• Developers working with LLM APIs frequently encounter millisecond timing outputs; a dedicated converter reduces low-grade interruption in debugging and benchmarking workflows.
• Small utility tools like this often fill gaps that larger platforms leave unaddressed, especially for LLM-specific developer ergonomics.
• Willison’s public tooling habit makes niche workflow friction visible and shareable across the developer community.

Simon Willison, Simon Willison’s Weblog · 2026-04-24 · Read the original