Is Auction Bid Calculator really free?

Yes. The auction and eBay calculators are unlimited and free with no account required. Amazon checks are limited to 10 a month with a free account and unlimited on Pro.

Which auction sites does Auction Bid Calculator work on?

It works on bidspotter.co.uk, bidspotter.com and i-bidder.com. The calculator opens on lot pages and reads the auction house commission rate automatically where it is published.

Does Auction Bid Calculator see my card details?

No. Payments are handled by Stripe and sign-in by Clerk. Card numbers never touch Auction Bid Calculator's servers.

Auction Fee Calculator UK | Commission, VAT & True Cost

Q: How accurate are the eBay fees?

The calculator models the UK rate card, including tiered final value fees by category, the fixed order fee, regulatory operating fee, seller-level adjustments, international fees and VAT. Estimates are for guidance and should be checked against eBay's fee pages before major decisions.

Q: Can I cancel Pro anytime?

Yes. You can manage your subscription through Stripe's self-service portal and keep Pro until the end of the period already paid for.

COMMISSION 15–25% the fee most bidders forget ✦ VAT ON FEES yes, VAT applies to the commission too ✦ INTERNET SURCHARGE 3–5% for bidding online ✦ LOT FEES small, fixed, sneaky ✦ COMMISSION 15–25% the fee most bidders forget ✦ VAT ON FEES yes, VAT applies to the commission too ✦ INTERNET SURCHARGE 3–5% for bidding online ✦ LOT FEES small, fixed, sneaky ✦ COMMISSION 15–25% the fee most bidders forget ✦ VAT ON FEES yes, VAT applies to the commission too ✦ INTERNET SURCHARGE 3–5% for bidding online ✦ LOT FEES small, fixed, sneaky ✦ COMMISSION 15–25% the fee most bidders forget ✦ VAT ON FEES yes, VAT applies to the commission too ✦ INTERNET SURCHARGE 3–5% for bidding online ✦ LOT FEES small, fixed, sneaky ✦ COMMISSION 15–25% the fee most bidders forget ✦ VAT ON FEES yes, VAT applies to the commission too ✦ INTERNET SURCHARGE 3–5% for bidding online ✦ LOT FEES small, fixed, sneaky ✦ COMMISSION 15–25% the fee most bidders forget ✦ VAT ON FEES yes, VAT applies to the commission too ✦ INTERNET SURCHARGE 3–5% for bidding online ✦ LOT FEES small, fixed, sneaky ✦ COMMISSION 15–25% the fee most bidders forget ✦ VAT ON FEES yes, VAT applies to the commission too ✦ INTERNET SURCHARGE 3–5% for bidding online ✦ LOT FEES small, fixed, sneaky ✦ COMMISSION 15–25% the fee most bidders forget ✦ VAT ON FEES yes, VAT applies to the commission too ✦ INTERNET SURCHARGE 3–5% for bidding online ✦ LOT FEES small, fixed, sneaky ✦

UK auction fee formula

How to calculate auction fees
before you bid.

Your true cost is more than the winning bid. Use the auction house's published terms for each part of the calculation:

Use the free web calculator

Start with the hammer price

This is the winning bid before fees. Multiply it by the buyer's premium rate to calculate the commission.

Add premium, VAT and surcharges

Add VAT on the buyer's premium, plus any online bidding surcharge and fixed lot fee. Check the catalogue terms: VAT may also apply to the hammer price or other charges for some lots.

Include delivery and resale costs

Add collection or delivery to get the all-in cost. If you plan to resell, compare that total with your proceeds after eBay or Amazon fees — not the headline sale price.

Three calculators, one sidebar

From hammer price to net profit,
without leaving the lot page.

A clean sidebar that opens on any BidSpotter or i-bidder lot. Commission rates are read from the page automatically — no hunting through terms & conditions.

🔨

True auction cost

Hammer price + commission + VAT + per-unit maths, computed live as you type. The commission % auto-fills from the lot page. Know your walk-away number before bidding opens.

Free · Unlimited

🏷️

eBay fee & profit engine

The full UK fee table — tiered final value fees, fixed order fees, regulatory fee, seller levels, international rates — for private and business sellers. With break-even and profit targets.

Free · Unlimited

📦

Amazon resale check

Type an ASIN, get live FBA fees, referral rates and the 30-day average Buy Box price. Instant net-profit and ROI verdict on flipping the lot to Amazon.

10 free / month · Unlimited on Pro

How it works

Three clicks between you
and a confident bid.

Open any lot

Browse BidSpotter or i-bidder as normal. Click the extension icon and the calculator slides in beside the lot — commission % already filled in.

See the true cost

Enter your intended bid. Every fee is added instantly — with and without VAT, per unit if you're buying multiples.

Check the resale

Flip to the eBay or Amazon tab to see fees, margins, break-even and profit targets. Bid when the numbers say yes — walk when they say no.

Pricing

Free where it can be.
Fair where it can't.

Auction and eBay maths run entirely in your browser — they're free, forever, no account needed. Amazon checks use live market data that costs us real money per lookup, so those are metered.

Free

£0

forever

Unlimited auction true-cost calcs
Unlimited eBay fee & profit calcs
Commission auto-fill on lot pages
Break-even & profit targets
10 Amazon resale checks / month (free account)

FOR SERIOUS FLIPPERS

Pro

£4.99 / month

or £49 / year — save 18%

Unlimited Amazon resale checks
Live FBA fees & referral rates
30-day average Buy Box pricing
Everything in Free, of course
Cancel anytime — takes two clicks

Questions

Fair questions, straight answers.

How do you calculate auction fees in the UK?

Start with the hammer price, then add the buyer's premium, VAT on the premium, any online bidding surcharge, fixed lot fees and delivery. Check the auction terms because VAT can also apply to the hammer price or other charges for some lots.

What auction fees does the calculator include?

Enter a hammer price and the calculator adds the buyer's commission, VAT on the commission, online bidding surcharges and fixed lot fees. It shows the all-in cost and the percentage paid above the hammer price before you bid.

Is it really free?

Yes. The auction and eBay calculators run locally in your browser and cost us nothing to serve, so they're unlimited and free — no account required. Amazon checks call live market-data APIs that charge us per lookup, which is why they're metered: 10 a month free with an account, unlimited on Pro.

Which auction sites does it work on?

bidspotter.co.uk, bidspotter.com and i-bidder.com. The calculator opens on any lot page and reads the auction house's commission rate automatically where it's published. More platforms are on the roadmap.

How accurate are the eBay fees?

We model the full UK rate card: tiered final value fees per category, the fixed order fee, regulatory operating fee, seller-level adjustments, international fees and VAT. Rates are served from our backend so updates reach you without an extension update. Estimates are for guidance — always confirm against eBay's own fee pages before making big decisions.

Do you see my card details?

Never. Payments are handled entirely by Stripe, sign-in by Clerk — two of the most trusted names in the business. Card numbers never touch our servers. See the privacy policy for the full picture.

Can I cancel Pro anytime?

Yes — two clicks from the extension ("Manage subscription") into Stripe's self-service portal. You keep Pro until the end of the period you've paid for. No retention dark patterns, no emails begging you to stay.

The hammer price is only half the story. Bid on the true cost.

YOUR REAL BILL