Dollar-Cost Averaging Calculator

Calculate average cost per share and total return from regular fixed investments.

Investment Parameters

Periodic Investment Amount ($)

Number of Periods

Price Series (comma or newline separated — one price per period)

If fewer prices than periods are provided, the last price is repeated.

Total Invested

$6,000.00

Total Shares

52.0952

Avg Cost / Share

$115.17

Current Price

$135.00

Current Value

$7,032.85

Total Return

+$1,032.85 (+17.21%)

Period Breakdown

Period	Price	Shares Bought	Running Avg Cost
1	$100.00	5.0000	$100.00
2	$90.00	5.5556	$94.74
3	$110.00	4.5455	$99.33
4	$95.00	5.2632	$98.21
5	$120.00	4.1667	$101.91
6	$105.00	4.7619	$102.41
7	$130.00	3.8462	$105.62
8	$115.00	4.3478	$106.70
9	$140.00	3.5714	$109.60
10	$125.00	4.0000	$110.97
11	$150.00	3.3333	$113.66
12	$135.00	3.7037	$115.17

About Dollar-Cost Averaging Calculator

Dollar-cost averaging (DCA) is an investment strategy where you invest a fixed amount at regular intervals regardless of the asset price. When prices are low you buy more shares; when prices are high you buy fewer. Over time this smooths out the average cost per share and reduces the impact of volatility. Enter your periodic investment amount, how many periods you invest, and the price at each period to see your average cost per share, total return, and a full period-by-period breakdown. All calculations run locally in your browser.

Built and maintained by Meet Shah · Last updated 19 July 2026

What this tool is used for

Seeing what average price a regular fixed investment would have achieved.
Comparing regular investing against a single lump sum on the same data.
Understanding why a fixed amount buys more units when the price is low.
Producing a figure to check against a broker's own statement.
Modelling a contribution schedule before committing to one.

Frequently Asked Questions

What does dollar-cost averaging actually do?: Buys more units when prices are low and fewer when high, because the amount is fixed rather than the quantity. That produces an average cost below the average PRICE over the period — a harmonic mean rather than an arithmetic one.
Does it beat investing a lump sum?: Historically no, about two thirds of the time — markets rise more often than they fall, so money invested earlier does better on average. DCA's value is behavioural and risk-shaped: it removes the timing decision and caps regret, which is why people stick with it.
Why is the average cost lower than the average price?: Because of how the fixed amount interacts with price. £100 buys 10 units at £10 and 20 at £5, so 30 units for £200 — an average cost of £6.67 against an average price of £7.50. The arithmetic favours you automatically.
Does it protect against loss?: No. It reduces the impact of buying everything at a peak; it does nothing about a market that falls and stays down. Any strategy that keeps buying into a permanent decline loses money, and DCA is not an exception to that.
Is a monthly contribution just DCA by another name?: Effectively yes, and it is the version almost everyone actually does — a pension or payroll investment is dollar-cost averaging by construction. The comparison with lump-sum investing only applies when you genuinely have a lump sum to deploy.

Common errors and gotchas

Ignoring fees and spreads, which matter most when contributions are small and frequent.
Treating a modelled average as a return, which needs the current price to mean anything.
Assuming the strategy reduces risk in every market, when it mainly reduces timing risk.
Using past prices as a forecast rather than as an illustration.
Overlooking tax treatment, which varies by jurisdiction and account type.