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Calculate crypto position size, stop loss and risk-to-reward

Use the Basis risk calculator and chart position tool to size long or short scenarios from account risk, entry, stop and targets.

8 min readUpdated 2026-08-224 sections

The calculator needs a real invalidation level

Position size is derived from the distance between entry and stop, the account value and the maximum loss you allow. A stop chosen only to create a larger position reverses the logic: structure should define invalidation, and risk should define size.

InputMeaning
Account valueCapital base used for the scenario
Risk % or amountMaximum planned loss if the stop fills
EntryExpected average execution price
StopPrice that invalidates the setup
TargetScenario objective used for R-multiple
LeverageMargin efficiency; it does not reduce price risk

Plan a position on the chart

  1. 01

    Mark invalidation

    Place the stop beyond the structure that makes the thesis wrong, with room for expected volatility.

  2. 02

    Set entry

    Use the price you can reasonably execute, not the candle extreme visible after the fact.

  3. 03

    Set allowed loss

    Choose a fixed account risk that remains tolerable across a losing sequence.

  4. 04

    Read size and R

    Basis calculates quantity, notional exposure, maximum loss and reward-to-risk.

  5. 05

    Stress the plan

    Consider slippage, fees, funding and a gap through the stop before accepting the size.

Leverage changes margin, not invalidation

Two positions with the same notional exposure and stop distance carry similar directional price risk even if one uses more leverage. Higher leverage reduces posted margin and moves liquidation closer; it does not make the thesis more accurate.

Important

Liquidation estimates are approximate and venue rules vary. Never use liquidation as the intended stop.

Use R-multiples to compare unlike trades

One R is the planned loss from entry to stop. Expressing outcomes in R makes a BTC scalp and an altcoin swing comparable even when their prices and sizes differ. Journal planned R and realized R separately; slippage and management often explain the gap.