Quarter Tankstock control for marketplace sellers
Fuel gauge for the selected product E F
Days to empty0
Last day to order-
Nov 1 Pour-over kettle 0 in stock

Scroll down the trip and the date moves. The needle drops with each day's sales.

A gas gauge on every product you sell.

You never run your car dry, because the dash says how far the tank will go and you know how far it is to the next station. Quarter Tank puts the same two numbers on every product you sell: days of stock left, and the last day to reorder before your supplier's lead time runs you onto E.

Reads your sales fromAmazonEtsyShopifyeBay
First gaugeabout 10 minutes after you connect, built from your last 12 months of orders. The morning stickers start at 7 a.m.
On the sign$39 a month, flat, every product. First 30 days free, no card.Connect a store
Drive the holiday season with Rosa's shop ↓

Drive November and December

Rosa sells kitchen and dog goods from a garage in Tucson, Arizona, on Amazon and Etsy. Pick a product on the dashboard and scroll. Every day of the season is a stretch of road, and the blue trace beside it is what's left in the tank. Press Fill up today when you think it's time. The dotted line is what Quarter Tank would have left on the same road.

The road through the season, with the stock level drawn beside it

Your drive

Quarter Tank's drive, same road

Fill-up size
Units0
Total$0
Per unit$0.00
Days it covers0
2 weeks, less cash parked2 months, fewer orders

How much to put in

A full tank is not free. Every unit sitting on a warehouse shelf is cash you can't spend, and the marketplace charges you for the shelf. Too small a fill-up and you're back at the pump every week.

Pick how long a fill-up should last. Quarter Tank turns that into units for each product using the sales it forecasts for the days after the delivery lands, holidays included, and the pump shows what it costs at your supplier's price.

30 days of kettles is 0 units.

The sticker on the windshield

The oil change place writes your next service on a little sticker in the corner of the glass. Quarter Tank writes one for each product, every night, and sends you the ones that are coming due. These are Rosa's, as of the day you've scrolled to.

What it did on last year's holiday drive

Every new car on the lot wears a label on the window that says what it will do. This is ours, from the 2,840 shops that drove November and December 2025 with a gauge on every product, measured against their own season the year before.

Stock Economyand cash parkedQuarter Tank · Nov 1 to Dec 31, 2025 · 2,840 shops
Days with nothing to sell, per best-seller1.6median shop · the season before: 11.4

The median shop kept

$5,940

in holiday sales it would have missed, and parked 14% less cash in stock while doing it.

Stockout rating
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
4.8 from 1,912 seller reviews

Shops that connected before Oct 1, 2025, against their own Nov to Dec 2024. Your mileage will vary with your suppliers.

Moonfern Candle Co.

Asheville, NC · Etsy + Shopify

Gauges on the dash
38
Dry days, Q4 2024
19
Dry days, Q4 2025
2

I used to find out I was out of the fig candle from a one-star review. Now a sticker tells me three weeks early.

Dana W., owner

Lowbark Dog Supply

Columbus, OH · Amazon FBA + eBay

Gauges on the dash
112
Black Friday to Cyber Monday
in stock
Cash parked, avg
$41k → $33k
Storage fees, Q4
−$1,180

It told me to order less of the leashes. Nobody has ever told me that.

Marcus T., runs it with his brother

Halfpine Print Shop

Duluth, MN · Etsy

Connected
12:31 pm
First gauges
12:40 pm

64 gauges before I finished my sandwich.

Priya N.

One price on the sign

No grades, no per-product charge. Connect your shop and every product you list gets a gauge, whichever marketplaces it sells on.

  1. Connect Amazon Seller Central, Etsy, Shopify or eBay. Read-only, through each one's own sign-in.
  2. Gauges on the dash for every product, from the last 12 months of orders.
  3. Your first stickers arrive, by text or email.
  • Reads orders, returns and inbound shipments, including Amazon FBA. A product you sell in two places counts once.
  • Knows each supplier's lead time and learns it from your real deliveries.
  • Never places an order for you. You press the pump.

Prices shown are this fictional product's.