Free Amazon seller tools — no login, all in your browser.

The same math we run on our own Amazon accounts, packaged as fast, free calculators. No signup, no upload to a server — every number stays in your browser. Built by Amazon sellers, for Amazon sellers.

New to this? Start with the 30-Second PPC Audit to grade your account, then the Waste Calculator to find the exact spend to cut. Selling a specific product? Run the FBA Profit and Break-Even ACoS calculators first, so you know your real margin before you touch a single bid.

Free AI tool

RedHen Labs PPC Review — a free GPT on ChatGPT

Paste in your campaign numbers and our custom GPT gives you a plain-English review of your Amazon PPC — where you're overspending and what to test next. Free, runs inside ChatGPT.

Open in ChatGPT ↗

Pick a free tool

30-Second PPC Audit

A–F grade, 0–100 score and estimated waste — no upload

PPC Waste Calculator

Your Search Term Report → wasted keywords + a copy-paste negative list

Break-Even ACoS Calculator

True max ACoS, target ACoS and max CPC — not the 25% rule

FBA Profit & Margin Calculator

Net profit, margin & ROI after every Amazon fee

Break-Even Price Calculator

The lowest price that still covers every fee

PPC Budget Calculator

How much to spend on ads — monthly & daily

Agency Cost Calculator

Flat fee vs % of ad spend, with the crossover point

Want this running automatically, every day?

These tools are the manual version. RedHen syncs the real fees Amazon billed you, tracks true profit per product, and queues PPC changes for your approval — flat fee, never a percentage of ad spend, with a 14-day free trial (card required, $0 today).

See flat-fee pricing