NFT Royalty Calculator

Enter the secondary sale price, your royalty percentage, and (optionally) the marketplace fee, and the calculator splits the proceeds between the marketplace, the seller, and you as creator. Run it once with the typical 5% royalty most marketplaces enforce, and once with the 10% creators often want, to see how much the difference actually means at typical floor prices.

Royalty enforcement is a moving target. Some marketplaces (OpenSea historically) enforce on-chain; others (Blur, X2Y2) made them optional or zero by default to compete on fees. The calculator shows what you'd earn IF the royalty is honored — not whether the marketplace will honor it.

For on-chain royalty enforcement, look at standards like ERC-2981 and registries like OpenSea's operator filter. Off-chain, it's a marketplace-by-marketplace policy question.

The split math: gross_sale → minus marketplace_fee → minus creator_royalty → seller receives the rest. Run with sale = 1 ETH, marketplace_fee = 2.5%, royalty = 5%: marketplace takes 0.025 ETH, creator takes 0.05 ETH, seller takes 0.925 ETH. Bump royalty to 10% and the seller drops to 0.875 ETH while creator earns 0.10 ETH — the seller's loss equals the creator's gain dollar-for-dollar. That's the tension. Marketplaces compete on fees and royalties because every basis point comes off the seller's bottom line.

Worked example: your collection has a 0.5 ETH floor and you've set a 7.5% royalty in the contract. Last month had 40 secondary sales averaging 0.6 ETH. Multiply: 40 × 0.6 × 0.075 = 1.8 ETH in nominal royalties. Now apply the enforcement reality: maybe 60% of those sales went through royalty-honoring marketplaces. Real royalties received: 1.8 × 0.6 = 1.08 ETH. The gap between nominal and received is what creators have been processing for the last two years.

Limitations to know: ERC-2981 declares the royalty on-chain via a function call but doesn't enforce payment — enforcement is the marketplace's choice. EIP-2981's predecessor schemes (manifold, async, custom) split similarly. Bridged copies on other chains don't pay your royalty unless you've deployed there too. Wash trading between two wallets you control nominally generates royalties but is recognized as wash trading by analytics platforms and most modern marketplace algorithms strip those volumes from any rankings or earnings displays.

Real-world enforcement landscape (rough state in modern markets): OpenSea historically enforced via the operator filter; coverage has shifted as marketplaces compete on fees. Blur and several aggregators made royalties optional or zero. LooksRare, X2Y2, and others vary. The result is that nominal royalties on a contract often translate to 30-70% of expected value actually received. Track real receipts vs nominal expectations after each marketplace cycle to see what's working.