neroidea
Neroidea Mini Tools

Small tools that do one thing well.

Handy browser utilities that load instantly and keep your data on your machine. No installs, no accounts, no uploads.

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Pinyin Annotator

Paste any Chinese text, get print-ready pinyin ruby. All local.

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Tianzige Worksheet Generator

Turn any characters into printable 田字格 tracing sheets. All local.

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Fullscreen Flag

Pick a country, hold your screen up high — the stadium flag that's always in your pocket.

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FBA Fee Calculator

2026 Amazon fees on one screen: referral, fulfillment, peak vs off-peak, the 3.5% surcharge.

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Etsy Fee Calculator

What Etsy takes per sale — transaction, processing, listing, ads, and the effective rate.

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eBay Fee Calculator

The 13.6% in full: final value fee on shipping and tax, the per-order fee, store rates and ads.

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Depop Fee Calculator

No selling fee in the UK, US and Australia — see exactly what a sale still pays.

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Poshmark Fee Calculator

Flat $2.95 under $15, 20% above — plus the Texas fee tax most calculators miss.

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Mercari Fee Calculator

The 10% that includes shipping — and the 3.6% your buyer pays on top.

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Marketplace Fee Comparison

One sale, six platforms: Amazon FBA, Etsy, eBay, Depop, Poshmark and Mercari — and what you keep.

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Image Compressor

Shrink JPG, PNG and WebP in the browser — pick a quality, a size cap, or a target in KB.

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kg to lbs Converter

Kilograms to pounds in one keystroke — both ways, exact factor, stones included.

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HEIC Converter

iPhone photos to JPG, PNG, WebP or PDF — in the browser, in batches, nothing uploaded.

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Starbucks Calorie Calculator

Pick your drink, size, milk and extras — official Starbucks nutrition, estimates flagged.

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More tools are on the bench.