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TRADING TOOLS / COST BASIS

Average down calculator.

Find your true average purchase price — then explore what another buy would actually change. Fees included, assumptions visible.

Spot purchasesExact decimal mathRuns locallyFee-aware
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01

Your purchase history

Add each buy. Use the same quote currency throughout (e.g. USD).

Price paid for one unit of the asset, in your chosen quote currency (e.g. USD).
Number of units acquired in this buy. Fractions such as 0.0025 BTC are supported.
Percentage buying fee applied to the value of this purchase. Enter 0.1 for 0.1%.
Additional flat purchase fee in quote currency, e.g. 2 USD. Use zero if none.
Optional market priceOptional

Enter your own quote to estimate unrealized performance.

Your own spot reference price (same quote currency as the purchases) for estimating unrealized profit or loss. Enter a manually checked price; this calculator does not fetch live market quotes.
Optional manual price. No live feed is provided.
Plan your next purchaseOptional

See how much you would need to buy to reach a target average.

Desired weighted average cost after another purchase. Some targets cannot be reached at a given purchase price.
Hypothetical price per unit for your next buy, not a forecast or a market order.
Advanced next-buy fees
Trading fee charged as a percentage of the value of your hypothetical next purchase.
Flat fee in quote currency added to the next purchase, independent of the percentage fee.
Blank fee fields count as zero. Enter 0.1 for a 0.1% fee. All figures use a single quote currency. No sales, tax lots, financing, spread, or slippage are modeled.
UNDER THE HOOD

The average is weighted.

Your average price is not the mean of the displayed prices unless you bought the same quantity each time. We add the cost of every purchase, including the entered fees, and divide by all units acquired.

Average cost = (Σ purchase cost + Σ buy fees) / Σ units

If your desired target is mathematically impossible at the planned purchase price and fee rate, the calculator explains why instead of presenting a misleading purchase quantity.

View full methodology ↗
COST BASIS / LEARN

What does an average purchase price actually mean? Follow fixed-dollar buys, a partial sale and a synthetic candlestick chart.

Read DCA & Average Cost ↗