Capital Gains Calculation

Accurate cost basis is critical. Get it wrong, and you'll either overpay tax or face penalties.

Cost Basis: Weighted Average Method

South Africa uses the weighted average cost method (WACM). When you sell, your cost is the average of all buys.

Example:

  • Buy 1 BTC at R100k
  • Buy 2 BTC at R110k
  • Sell 1.5 BTC at R120k

Weighted cost = (1×100k + 2×110k) / 3 = R106,667

Gain per unit = R120k - R106,667 = R13,333

Total gain = 1.5 × R13,333 = R20,000

Calculating Gains

Gain = Selling Price - Cost Basis

Include all costs: exchange fees, transfer fees, conversion fees.

SA Tax Liability

Taxable gain = Total gain × 40% (inclusion rate)

Tax owed = Taxable gain × Your marginal tax rate

After R40,000 annual exemption:

  • 18% bracket: 40% × 18% = 7.2% effective
  • 26% bracket: 40% × 26% = 10.4% effective
  • 41% bracket: 40% × 41% = 16.4% effective

Using the CGT Calculator

Our calculator handles weighted average automatically. Input your buy/sell transactions, and it computes your liability.