Capital Gains Tax Calculator

Estimate how much tax you may owe when selling shares, property, cryptocurrency, or other assets at a gain. This page also keeps the formula, examples, FAQs, and references close by so you can check the result with confidence.

What This Capital Gains Tax Calculator Helps You Do

The calculator applies an allowance first, then taxes the remaining gain at the basic or higher rate depending on your income and asset type. Review the formula and examples below if you want to see how the result is derived.

This page is meant to give you a fast answer, but it also helps you double-check the math before you make a decision. Start with the inputs that you already know, run the calculation, and then compare the output with the formula, examples, and FAQs below so you can see whether the answer fits the situation you are modeling.

If the result looks off, the usual causes are a unit mismatch, a missing decimal, the wrong scenario, or a value that needs to be entered as a rate instead of a total. The notes on this page are designed to make those checks easy without forcing you to leave the calculator and search for context elsewhere.

  • Use the calculator first for a quick estimate.
  • Use the formula to understand how the result is built.
  • Use the examples to compare common use cases.
  • Use the references when the answer depends on a standard or assumption.

Common Checks

A quick result is useful, but the best result is one that still makes sense when you look at it a second time. If you are comparing scenarios, try changing one input at a time so you can see which variable has the biggest impact on the final answer. That makes it much easier to spot whether the calculation matches your expectations.

It also helps to keep the context of the problem in mind. A calculator can tell you the math, but you still need to decide whether the input represents a total, a rate, an average, or a category-specific assumption. When in doubt, start with a simple example from the page and scale up from there.

  • Check that every unit matches the rest of the problem.
  • Keep rates, totals, and averages separate.
  • Adjust one variable at a time when testing scenarios.
  • Use the smallest realistic input first, then scale upward.

Scenario Planning

This calculator is especially useful when you want a quick answer before you commit time, money, or effort. Try one baseline input set, then change a single number and compare the result so you can see how sensitive the answer is to that variable.

That makes the page useful for more than just arithmetic. It becomes a small decision aid that helps you compare options, test assumptions, and explain the final number with confidence when you need to share it with someone else.

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Result

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Quick Answer: The calculator applies an allowance first, then taxes the remaining gain at the basic or higher rate depending on your income and asset type. Review the formula and examples below if you want to see how the result is derived.

How to Calculate Capital Gains Tax Calculator

  1. Enter the gain: Add the profit you made from the sale.
  2. Enter income and asset type: These inputs decide which rates apply.
  3. Review the after-tax amount: The result shows tax and remaining profit.

Capital Gains Tax Calculator Formula

CGT = taxable gain × rate, with part of the gain potentially taxed at the basic rate and the rest at the higher rate
Variable Meaning Unit
Capital gains Profit from the sale before tax $
Annual income Your total annual income $
Asset type Shares, property, crypto, or other assets -

Worked Examples

USA - UK-style example with a house
  • Capital gains: £40,000
  • Annual income: £45,000
  • Asset type: Property

Result: £7,229 tax

Omni's worked example splits the gain across the basic and higher rates.

UK - Shares example
  • Capital gains: £40,000
  • Annual income: £30,000
  • Asset type: Shares

Result: Lower tax on the portion above the allowance

Shares are usually taxed at the 10% and 20% CGT rates.

EU - Crypto example
  • Capital gains: £15,000
  • Annual income: £20,000
  • Asset type: Cryptocurrency

Result: Tax on the amount above the allowance only

Cryptocurrency uses the same basic and higher rates as shares on this calculator.

How to Interpret Your Results

Range Meaning Action
No tax The gain was covered by the allowance There may be no capital gains tax due.
Basic-rate band Part of the gain is taxed at the lower rate Check how much income remains below the threshold.
Higher-rate band The remaining gain is taxed at the higher rate A larger gain or higher income increases the tax bill.

Frequently Asked Questions

Yes. The calculator removes the allowance before applying tax rates.

Property gains are taxed more heavily in the UK-style rules used here.

Yes. If the gain is below the allowance, the estimated tax is zero.
Planning note: Tax rules change over time. Verify the current allowance and rates with official guidance before filing.

References

Last reviewed: March 2026