Investing

Stock Average Calculator

Average cost after buying more shares.

Enter your values

First purchase shares

Enter the first purchase shares you are working with.

First purchase price($)

Enter the first purchase price in $.

Second purchase shares

Enter the second purchase shares you are working with.

Second purchase price($)

Enter the second purchase price in $.

Current price($)

Enter the current price in $.

Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.

Results

New average cost: $38.66
Total shares: 250
Total invested: $9,665.00
Current value: $9,100.00
Unrealised P/L: -$565.00 (-5.85%)
Break-even price: $38.66

Working

1Avg = (100×$48.50 + 150×$32.10) ÷ 250 = $38.66

Quick answer

Average cost is total money spent divided by total shares held across all purchases.

Avg = (q₁p₁ + q₂p₂) ÷ (q₁ + q₂)

At a glance

What it does	Average cost after buying more shares.
Category	Investing
Inputs needed	First purchase shares, First purchase price, Second purchase shares, Second purchase price, Current price
Main output	New average cost
Formula	Avg = (q₁p₁ + q₂p₂) ÷ (q₁ + q₂)
Cost	Free — no sign-up, no download

How to use the Stock Average Calculator

1Enter your first purchase quantity and price.
2Enter the second purchase.
3Add the current price to see unrealised profit.

Inputs explained

First purchase shares: Enter the first purchase shares you are working with.
First purchase price($): Enter the first purchase price in $.
Second purchase shares: Enter the second purchase shares you are working with.
Second purchase price($): Enter the second purchase price in $.
Current price($): Enter the current price in $.

Worked example

Using the values the calculator loads with:

Inputs

First purchase shares100
First purchase price48.50 $
Second purchase shares150
Second purchase price32.10 $
Current price36.40 $

Results

New average cost$38.66
Total shares250
Total invested$9,665.00
Current value$9,100.00
Unrealised P/L-$565.00 (-5.85%)
Break-even price$38.66

Avg = (100×$48.50 + 150×$32.10) ÷ 250 = $38.66

Frequently asked questions

Is averaging down a good idea?

Only if your thesis still holds. Adding to a losing position purely to lower the average is how small losses become large ones.

Do fees count in cost basis?

Yes — include commissions in the purchase price for accurate tax reporting.

What do I need to enter into the Stock Average Calculator?

Just 5 values: first purchase shares, first purchase price, second purchase shares, second purchase price, current price. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.

How does the Stock Average Calculator work out the answer?

Average cost is total money spent divided by total shares held across all purchases. It applies the formula Avg = (q₁p₁ + q₂p₂) ÷ (q₁ + q₂) and shows the working so you can check each step by hand.

Is the Stock Average Calculator free, and do I need an account?

It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.

Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.