How to Calculate Mid-Year Discounting in a DCF Model

Published 2026-04-21 · SFS Models

End-of-year discounting under-discounts cash flows by half a year of WACC. Mid-year discounting fixes this. Here's the formula, the Excel implementation, and the common mistakes.

If you've built a DCF model in Excel and used standard end-of-year discounting, you're systematically under-valuing the business by approximately half a year of WACC. On a growth business, that's a 5-10% understatement of enterprise value. Mid-year discounting fixes this.

What is mid-year discounting?

In a standard DCF, you discount each year's free cash flow (FCF) back to present value using:

PV = FCF / (1 + WACC)^t

Where t is the number of years from the valuation date.

The problem: this formula assumes all of year t's cash flow arrives on December 31st of year t. In reality, cash flows arrive throughout the year — roughly evenly. The "average" cash arrives at mid-year (June 30th).

Mid-year discounting adjusts for this by discounting cash flows by half a period less:

PV = FCF / (1 + WACC)^(t - 0.5)

For a 5-year forecast at 10% WACC, mid-year discounting gives you ~4.7% higher PV vs end-of-year. On a $1bn EV business, that's $47m of value.

When to use mid-year vs end-of-year

Use mid-year when:

Cash flows arrive evenly throughout the year (most operating businesses)
You're presenting valuations to investment committees who expect mid-year (standard at most US PE firms)
Public company valuations (most sell-side equity research uses mid-year)

Use end-of-year when:

Cash flows are heavily back-loaded (project finance, infrastructure concessions where cash arrives at completion milestones)
You're modelling for tax-driven structures where year-end timing matters
The receiving institution has a stated convention (some EU banks default to end-of-year)

The terminal value adjustment

Most DCF builders forget that mid-year discounting also affects terminal value. Two adjustments:

1. Discount the terminal value back further.

If your explicit forecast ends in year 5 and you've used mid-year discounting for years 1–5, the terminal value (which represents value FROM year 6 onwards) should be discounted at:

TV PV = TV / (1 + WACC)^(5 - 0.5) = TV / (1 + WACC)^4.5

NOT TV / (1 + WACC)^5.

2. The terminal value formula doesn't change.

The Gordon growth formula gives you the value AS OF the end of the explicit forecast period. So whether you use mid-year or end-of-year, the TV formula itself is:

TV = FCF(year n+1) / (WACC - g)

Only the discount factor applied to bring TV back to present value changes.

Implementing mid-year discounting in Excel

Add a "discount factor" row to your DCF tab that applies mid-year automatically:

Year:           1     2     3     4     5
FCF:            100   120   140   160   180
Discount factor: 1/(1+WACC)^0.5  1/(1+WACC)^1.5  1/(1+WACC)^2.5  ...

PV = FCF × Discount factor

Sum the PVs of years 1–n + discounted terminal value = enterprise value.

For our DCF Model, we built in a toggle on the INPUTS tab — switch between mid-year and end-of-year and the entire model recalibrates.

Common mistakes

Discounting terminal value at year n + 1 instead of n. TV represents value at end of year n, so discount it at year n (or year n − 0.5 for mid-year).
Using mid-year for one year and end-of-year for others. Be consistent across all years in the explicit forecast.
Ignoring stub periods. If your valuation date isn't year-end, the first period is a stub (e.g., 7 months). Adjust the discount factor for the stub period accordingly.
Mid-year on a project that ends in year 5. If the business has a defined termination (project finance), don't use mid-year for the final year — use the actual cash receipt timing.

Free DCF model

If you want to skip the build, our free DCF Lite has both end-of-year and mid-year discounting available as a switch.

For the full version with three-statement integration, terminal value cross-check, and 8 integrity checks: DCF Model Excel Template.

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