If I buy more shares at this price, what will my new average be?

Enter all prices in the same unit

For example, all in pence or all in pounds. Results are in the same unit.

Try an example

Your holding

Shares you hold

Your average price per share

Including any past costs you want to include

Your new purchase

Shares to buy

Price per new share

The current price, or one you want to test

Your new average

Enter the shares you hold

Excludes dealing fees and taxes.

Have a target average?

Target average

Enter the shares you hold

Buying more can lower your average, but it also increases the amount invested in this share.

Show the calculation

Enter your figures to see each step.

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Anyone with the link can see the figures.

Worked example

Prices in pence

You hold 2,500 shares at an average of 152.4p. The price has fallen to 98.6p, and you look at buying 1,000 more.

• Cost of the shares you hold: 2,500 × 152.4 = 381,000
• Cost of this purchase: 1,000 × 98.6 = 98,600
• New average: (381,000 + 98,600) ÷ 3,500 = 137.0286p

To bring your average down to 120p, you would need to buy 3,786 shares. That gives an average of 119.9968p and costs 373,299.60p. All the prices are in pence, so every result is in pence too.

A holding with part of a share

You hold 100.5 shares at an average of 2.50, and you look at buying 50 more at 1.75.

• Cost of the shares you hold: 100.5 × 2.50 = 251.25
• Cost of this purchase: 50 × 1.75 = 87.50
• New average: (251.25 + 87.50) ÷ 150.5 = 2.2508

To reach a target of 2.10, you would need to buy 114.8572 shares, for an average of 2.10 and a cost of 201.00. You entered part of a share, so the answer is in part shares too, rounded up to 4 decimal places.

What this includes and excludes

• Includes: the shares you hold, the average price you enter for them, and one new purchase of the shares you enter at the price you enter.
• Excludes: dealing fees and commission, stamp duty and other taxes, currency conversion, tax on any gain, dividends, and any purchase other than the one you enter. It doesn’t fetch prices.
• Assumes: all prices are in the same unit.

This calculator does not calculate your taxable gain or loss. UK share tax calculations can involve same-day, 30-day and Section 104 rules. HMRC explains them in its Shares and Capital Gains Tax helpsheet (HS284) ↗ (opens in a new tab).

It doesn’t say whether to buy.

Figures are rounded for display

The calculator works with your exact figures and rounds only what it shows you:

• Averages are shown to 4 decimal places, or more if you entered a price with more. Trailing zeros are dropped, down to 2 decimal places.
• Costs are shown to 2 decimal places, or as a whole number when they are exactly whole.
• Shares to buy (for a target) are rounded up, never down, so the purchase always reaches your target. If the shares you hold and the shares to buy are whole numbers, the answer is rounded up to a whole number. If either has part of a share, the answer is rounded up to 4 decimal places; your platform’s precision may differ.
• Total shares after the purchase are shown in full, never rounded.
• The prices you enter are shown as you typed them, never rounded.
• A figure above 0 that would round to 0 is shown as “less than 0.0001” or “less than 0.01”, never as 0.
• In “Show the calculation”, the figures in each step are exact, so you can check every step. A result marked “≈” has been rounded by the rules above.