Amazon Sub Same Day Bid Calculator
Enter one ASIN's numbers to see the most you can pay per unit for a Sub Same Day placement, before faster delivery starts costing you margin.
How the Bid Ceiling Is Calculated
Amazon's Sub Same Day Placement Reservation program asks for a per-unit fee, per ASIN, every month in Capacity Manager. There is no published fee schedule, so the right number depends on margins only you know.
You Pay on Every Two-Hour Unit
The fee applies to every unit that ships two-hour, including the ones you would have sold at normal Prime speed. Worked examples that charge it only on the extra orders overstate what you can afford about nine times over at a 12% lift.
- Sales still rise, so a fee set too high looks like it is working.
- Margin leaks on every unit you would have sold anyway.
- A granted request locks 30 days before its placement period.
Bid Ceiling = Lift ÷ (1 + Lift) × Margin
At a 5% lift, 5 of every 105 two-hour units are new. That share, times what each unit earns, is the most each unit can carry.
- Margin is the price after any promo, minus product cost, referral fee, and FBA fee.
- Ad cost per unit is price × ACoS × share of sales from ads.
- Hold the ad budget flat and extra units carry no ad cost. Keep ACoS steady and they carry their share.
What to Do With Your Result
Skip
The fee room is too small to survive a wrong guess on lift. Put the effort into Prime coverage, stock, and the listing instead.
Test Small
Request one or two ASINs, bid at or under the ceiling, and compare contribution margin against the month before.
Worth a Test
A good candidate if shoppers need it fast. Still bid under the ceiling, check the request deadline, and point your ads at the two-hour offer.
Thresholds are Trellis' rule of thumb for leaving room for error, not Amazon guidance. Set the fee from the price you will actually sell at in that month.
Sub Same Day Bidding Questions
What is Amazon's Sub Same Day Placement Reservation program?
An invite-only FBA program where you set a per-unit fee to place eligible ASINs in Amazon's 2-to-5-hour delivery network. You pay that fee only on units that ship through it, on top of standard FBA fees.
How much should I bid for Sub Same Day?
No more than your expected lift divided by (1 + lift), times your per-unit margin. At a 12% lift that is about 11% of margin; at 5% it is under 5%.
Why does the fee apply to sales I would make anyway?
Amazon charges the fee on every unit that ships through Sub Same Day, not only the extra units faster delivery creates. At a 5% lift, about 100 of every 105 two-hour units would have sold at standard Prime speed.
Should I keep ACoS steady or hold my ad budget flat?
It depends on your plan if sales rise. With the budget held flat, extra units carry no ad cost, so the ceiling uses margin before ads. If you scale spend to hold ACoS steady, extra units carry their share of ad cost and the ceiling is lower. Most teams land between the two.
Is Sub Same Day worth it during Black Friday and Cyber Monday?
Usually not. Deal shoppers buy on price, discounts cut margin, and higher volume means paying the fee on more units that would have sold anyway. The last days before Christmas, after standard shipping cutoffs, are the stronger window.
Does the calculator save my numbers?
No. It runs in your browser, and nothing you enter is saved or sent.
Why BFCM Pushes Your Ceiling Down
Our breakdown covers how the program works, what our FBA vs FBM data says about faster delivery, and when a Sub Same Day test is worth running.