IconVault's Pinyin Converter turns Chinese text into Pinyin romanization so you can read pronunciation at a glance. Paste any Chinese text and get character-by-character output with each character shown alongside its Pinyin in brackets, for example 你(nǐ)好(hǎo). Choose from three tone styles: tone marks (hàn yǔ), tone numbers (han4 yu3), or no tones (han yu).

It is free and runs fully in your browser; the Pinyin dictionary loads on demand the first time you convert (a few hundred KB) and is then cached. The honest caveat: Pinyin reflects the most common reading of each character, and characters with multiple readings use the default one, so learners should double-check tones for polyphonic characters in study contexts.