semku

Average down calculator

Enter what you hold and what you plan to buy to see the new average cost and the total invested.

Currently held

Additional purchase

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How averaging down is calculated and what is supported

The new average cost is a weighted average: add up quantity × price for every purchase, then divide by the total quantity. A list of several purchases is calculated the same way.

Target average mode uses the quantity held N, the current average A, the purchase price B and the target average T to calculate the quantity needed. If the result is negative or has no finite solution, no number is produced and the reason is shown instead.

Internal calculations keep the full input precision and round once, for display only. Ordering the displayed quantity can give a slightly different average, so the expected average for that order is shown separately. Sales, fees, taxes, exchange rates and realized gains or losses are not included.

Frequently asked questions
What does an average down calculator do?
It calculates how your average purchase price changes when you combine what you already hold with an additional purchase. It does not judge whether buying more is a good idea or recommend a purchase.
How many shares do I need to buy to bring my average down to the current price?
If your current average differs from the current price, no finite quantity bought at that price makes the average exactly equal to it. semku does not suggest an arbitrary quantity; it tells you the target cannot be reached.
Can I use decimal quantities, for example for crypto?
Yes. Calculations keep the full input precision, and quantities are displayed to two decimal places. A display of 0.00 does not necessarily mean the underlying value is 0.
Can I calculate in a currency other than US dollars?
You can switch the currency symbol between USD, EUR and GBP. Amounts are calculated in the currency you enter; live exchange rates and currency gains are not applied.
Are fees and taxes included?
No. The result is the average cost from purchase prices and quantities only, and may differ from the actual order or settlement amounts.

Privacy on this page

Calculations run in your browser. The quantities, prices and amounts you enter are not sent to the server or saved in browser storage. Reloading the page returns the inputs to their initial state.

To understand how the page is used and to improve the service, this page sends semku’s own usage statistics and automatic error reports. They go only to the dedicated endpoint under semku.com/api/telemetry/v1/. They are not used for advertising or third-party tracking.

The usage statistics include the stage of use (such as starting an operation or requesting a copy), the time it happened and fixed identifiers that distinguish the page and feature. They do not include the quantities, prices or amounts you enter, the results shown or the text you copy. Inputs are not sent as hashes or as size categories either. The full URL and search terms are not sent.

Operations and sessions are distinguished by randomly generated identifiers. In the browser these exist only in temporary memory and are not written to cookies or browser storage. No identification based on cookies or combined device characteristics is used.

Error reports contain the error type, code and time, and, where available, a registered program-source identifier with the line and column number. The error message text and stack traces are not sent. Usage statistics and error reports also carry the site identifier, the published build and a random record identifier. IP addresses and user-agent strings are not part of these items.

The feedback form sends the rating you chose and the text you typed in the free-text field when you press the send button. A random ID that distinguishes the submission, the page, site and published build, and the type of request are also sent. There are no fields for your name, email address or phone number, and the values you enter are not attached automatically. Whatever you write in the free-text field is sent as is. Please do not enter personal data, passwords, authentication keys or payment details.

Separately, when you visit the site, the hosting provider records your IP address, the time of the request and user-agent information about your browser and device in Cloudflare Pages’ standard access logs.

For details, see the privacy policy in Korean.

Calculations run in your browser without sending the financial values you enter to the server or storing them. Fees, taxes, exchange rates and realized gains or losses are not included. Results are a reference for calculation only and are not investment advice or a guarantee of returns.