Dollar Cost Averaging Calculator

Model regular fixed investments and the average cost per unit that averaging achieves.

About Dollar Cost Averaging Calculator

Buying a fixed amount of money each period buys more units when prices are low and fewer when high, so the average cost is the harmonic mean of the prices — always at or below the simple average. That is the mathematical benefit of averaging in. Dollar-cost averaging cannot beat a lump sum in a rising market, but it does guarantee an average cost below the arithmetic average price, which limits timing regret.

Formula

Dollar Cost Averaging

Units = Σ (amount ÷ price each period); average cost is the harmonic mean of the prices

average cost per unit: Total invested divided by units acquired
harmonic mean: The averaging that a fixed-money purchase schedule produces

Worked example

With the default values below, Dollar Cost Averaging Calculator returns Units Acquired of 106.1538. Change any input above and every figure here is recalculated in your browser.

Inputs used

Amount invested each monthminimum 0: 500
Number of monthsaccepts 1–480 months: 24 months
Unit price at the startminimum 0.01: 100
Unit price at the endminimum 0.01: 130

Results

Units Acquired: 106.1538
Average Cost per Unit: $113.0435
Total Invested: $12,000.00
Final Value: $13,800.00
Total Return: 15.00%

Step by step

1Values used
2Dollar Cost Averaging
3Units Acquired= 106.1538
4Average Cost per Unit= 113.0435
5Total Invested= 12,000.00
6Final Value= 13,800.00
7Total Return= 15.00

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Dollar Cost Averaging calculated?

Units = Σ (amount ÷ price each period); average cost is the harmonic mean of the prices Buying a fixed amount of money each period buys more units when prices are low and fewer when high, so the average cost is the harmonic mean of the prices — always at or below the simple average. That is the mathematical benefit of averaging in.

Why does Dollar Cost Averaging matter?

Dollar-cost averaging cannot beat a lump sum in a rising market, but it does guarantee an average cost below the arithmetic average price, which limits timing regret.

What values do I need to enter?

This calculator takes 4 inputs: Amount invested each month, Number of months, Unit price at the start, Unit price at the end. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.