Build a contract from ten skins of one rarity (or five Coverts for a knife) and see every outcome: odds, output Float, marketplace price, liquidity and profit after fees. Or the other way round: name the skin you want and we’ll find the inputs.
93collections in the base1,446skins for trade-ups500knives and gloves as outputs
110 skins of one rarity: each adds 10% to its collection’s chance (20% for five Covert skins), and a collection’s chance is split evenly between its skins of the next rarity.
2The output Float is calculated from the input skins’ Float, adjusted for their ranges: a lower input Float means a lower output Float.
35 Coverts give a knife or gloves from their collection’s case. Prices are Steam or trusted marketplaces, your choice; liquidity is sales per week.
Which skin do you want to get?
We’ll find the collection, the input rarity and the cheapest set of skins with this outcome.
TargetM4A4 | HellfireThe Operation Hydra CollectionFloat with this set: 0.50, Battle-Scarred
Input10 skinsRestrictedChance33.3%out of 3 outcomesInput from$125cheapest set
All 10 input skins come from “Operation Hydra”: it gets 100% of the weight, split equally between its skins of the target’s rarity — there are 3.
Cheapest inputP90 | Death GripFloat 0.9999, Battle-Scarred10 × $12Lower input Float means lower output Float: in the builder you can adjust Float and swap any skin for another one from this collection.
Plans: cheaper and with fillers
How a trade-up works
A CS2 mechanic: you give 10 skins of one rarity and get one skin of the next rarity from the input collections. Since the 22 October 2025 update, five Covert skins from cases can be traded for a knife or gloves from those cases. Since 22 May 2026, Souvenir skins can be inputs too — alongside normal ones, and the result is always normal; stickers cannot be used.
Each input skin adds 10% weight to its collection (20% in a Covert contract). A collection’s weight is split equally between its skins of the next rarity. For example, 6 skins from one collection and 4 from another, with two next-rarity skins in each, give 30%, 30%, 20% and 20%.
For each input skin we take its position within its own Float range, average those positions and map the result onto the output skin’s range. So what matters is not the Float itself but where the skin sits in its range: the closer the input Float is to the bottom of the range, the lower the output Float.
A reverse search: you name the skin you want, and the calculator shows which collection and rarity to build it from, the odds and the cheapest input set. For a knife or gloves it’s five Coverts from the collection of the case that contains it. “Move to builder” puts the set into a contract where you can adjust Float and swap any skin.
No: all skins in a contract are either StatTrak™ or normal. StatTrak™ gives StatTrak™, and in a Covert contract StatTrak™ gives only knives — gloves have no StatTrak™. Souvenirs mix with normal skins but not with StatTrak™: a slot has a “Souvenir” switch when the skin has that version.
The calculator deducts the Steam fee when selling the result: the buyer pays the price, the seller gets the price divided by 1.15 — Steam keeps about 13%. It also computes the average profit: the sum of “chance × price after fee” over all outcomes minus the input cost. The fee switch in the summary changes the calculation.
Steam prices: inputs at the 7-day sales median, outcomes at a cautious sale price: a rare outcome no higher than the 30-day median and no more than twice the marketplace price, and Steam does not allow selling above $2000; 13% fee. Marketplace prices: inputs at the second-lowest price among trusted marketplaces (the cheapest listing is often a single item), outcomes at the lowest one, minus that marketplace’s seller fee (CSFloat 2%, Skinport 8%, SkinBaron 15%; 5% where the fee isn’t published). The modes do not mix: Steam wallet funds and marketplace money are different money. Items bought on a marketplace arrive by trade and are trade protected for 7 days — they can go into a contract only after that, and prices may change meanwhile.
Liquidity is how many sales there were in a week. A rare outcome’s median rests on a few sales, and selling at it can take a while.
Prices are from trusted marketplaces: inputs at the second-lowest price, outcomes at the lowest, minus that marketplace’s seller fee. Float, stickers and pattern of the result are not counted in the price. This is a calculation, not advice: a contract in the game cannot be undone.
M4A4 | Hellfire
P90 | Death GripLower input Float means lower output Float: in the builder you can adjust Float and swap any skin for another one from this collection.