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calcthai.com · Monthly DCA Investment Calculator
Money & tax
Monthly DCA Investment Calculator
See how a portfolio could grow with the same investment every month, including a starting lump sum, purchase fees and yearly increases, with a year-by-year table.
Year-by-year value
| Year | Cash invested | Portfolio value | Gain |
|---|---|---|---|
| 1 | 60,000.00 | 61,932.64 | 1,932.64 |
| 2 | 120,000.00 | 127,581.24 | 7,581.24 |
| 3 | 180,000.00 | 197,168.76 | 17,168.76 |
| 4 | 240,000.00 | 270,931.53 | 30,931.53 |
| 5 | 300,000.00 | 349,120.06 | 49,120.06 |
| 6 | 360,000.00 | 431,999.90 | 71,999.90 |
| 7 | 420,000.00 | 519,852.54 | 99,852.54 |
| 8 | 480,000.00 | 612,976.33 | 132,976.33 |
| 9 | 540,000.00 | 711,687.56 | 171,687.56 |
| 10 | 600,000.00 | 816,321.45 | 216,321.45 |
Ask about this page
The AI assistant answers only questions about the calculator on this page.
See how a portfolio could grow with the same investment every month, including a starting lump sum, purchase fees and yearly increases, with a year-by-year table.
How it works
The annual return becomes a monthly rate j = (1 + r)^(1/12) − 1. The lump sum and each monthly amount lose the purchase fee, are invested at the start of the month and grow at j to month-end. With a yearly increase, the monthly amount in year y = monthly amount × (1 + increase)^(y − 1). Gain = portfolio value − all cash paid, including fees.
A simple check: THB 5,000 a month for 10 years at 0% with no fee ends at THB 600,000, equal to cash paid. A 1% purchase fee leaves THB 594,000. At 12% a year, THB 1,000 a month for one year uses j ≈ 0.9489% and reaches about THB 12,766.
Real returns are not constant and losses are possible. The table is not a guarantee or advice to buy any fund. Dividend tax, redemption fees, bid-offer spreads and tax-deduction conditions of particular fund types are excluded.
Frequently asked questions
Does DCA beat investing a lump sum?
Not always. DCA spreads purchase timing and builds discipline, but in a steadily rising market money invested later earns less. This tool uses a constant return, so it does not model monthly volatility.
Where should ongoing fund fees go?
Deduct annual fund expenses from the expected return before entering it. The purchase-fee field is for fees charged on every purchase.
Why does cash invested include fees?
That is the cash that actually left your pocket, so gain is measured against all of it rather than only the part that bought units.
Sources
Method last verified 21 Sep 2026