MarginLog - eBay says you made $50. MarginLog says $31. Now you know.
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Resellers on eBay, Poshmark, Mercari, and 4 other platforms constantly underestimate how much fees eat into profit. MarginLog lets you log a sale in 30 seconds — sale price, what you paid, shipping — and shows your true net profit after every platform fee, automatically.
Free during beta. No card required. Also includes free profit calculators for all 7 platforms — no signup needed.
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Hey Product Hunt 👋
I built MarginLog after losing track of whether I was actually making money reselling.
The math sounds simple: sale price minus what you paid. But then eBay takes 13.25% + $0.30. Poshmark takes 20%. Shipping eats another few dollars. And suddenly the $22 profit you thought you made is actually $8.
MarginLog fixes this. Log a sale in ~30 seconds. It knows every platform's fee structure and does the math for you — true net profit, ROI, and which platform is actually worth your time.
What's free forever:
Profit calculators for eBay, Poshmark, Mercari, Depop, Etsy, Facebook Marketplace, and Vinted — no signup needed: marginlog.net/calculators
Compare all 7 platforms side by side: marginlog.net/calculators/compare
The full app (free during beta): https://marginlog.net
Log sales in 30 seconds
Dashboard showing profit trends and platform analytics
CSV export for tax season
Would love any feedback — especially from resellers who've tried other tracking methods (spreadsheets, notebooks, nothing). What's the biggest thing you'd want to see added?
MarginLog is live! Find it at: https://marginlog.net
Quick tool for resellers who want the real number before they list or after they sell.
Enter your sale price, what you paid, and shipping. It deducts the platform fee automatically — eBay, Poshmark, Mercari, Depop, Etsy, Facebook Marketplace, Vinted — and shows true net profit and ROI.
There's also a side-by-side comparison if you're deciding which platform is worth listing on.
Free. No account. No email.
Link: marginlog.net/calculators