Additional Funds Needed (AFN) Calculator (percent-of-sales method)

Understanding the additional funds needed (AFN) calculator — concept and principle

This calculator estimates how much outside money a company must raise to support next year's sales growth, using the percent-of-sales method, and the growth rate it could reach with no outside funds. Finance students and planners use it for a first financing forecast.

Growth needs money — with the default inputs: $128,000.

How it is calculated

AFN = (A0 ÷ S0) × ΔS − (L0 ÷ S0) × ΔS − M × S1 × RR

S0 = last year's sales; S1 = S0 × (1 + growth); ΔS = S1 − S0
A0 = assets that grow with sales; A0 ÷ S0 is capital intensity
L0 = spontaneous liabilities (accounts payable and accruals), not bank loans or bonds
M = net profit margin; RR = retention ratio = 1 − dividend payout ratio

Growth rate needing no outside funds: g = M × RR ÷ (A0/S0 − L0/S0 − M × RR).

The principle

Assets and spontaneous liabilities are assumed to stay a fixed percentage of sales. If sales rise 20%, receivables, inventory and capacity rise 20%. Part is financed spontaneously by supplier credit and accruals, part by retained profit; the rest must come from loans, bonds or shares. A negative result is a surplus.

Worked example

Defaults: sales 2,000,000; growth 20%; assets 1,200,000; spontaneous liabilities 200,000; net margin 5%; payout 40%.

S1 = 2,000,000 × 1.20 = $2,400,000; ΔS = $400,000.
Required increase in assets = 1,200,000 ÷ 2,000,000 × 400,000 = 0.6 × 400,000 = $240,000.
Spontaneous increase in liabilities = 0.1 × 400,000 = $40,000.
Addition to retained earnings = 0.05 × 2,400,000 × 0.60 = $72,000.
AFN = 240,000 − 40,000 − 72,000 = $128,000.
Zero-AFN growth = 0.05 × 0.6 ÷ (0.6 − 0.1 − 0.03) = 0.03 ÷ 0.47 = 6.4%.

Each point is the calculator re-run with only “Assets that grow with sales (total assets last year)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Assets that grow with sales (total assets last year)	Additional funds needed (− = surplus)
300,000	-$52,000
600,000	$8,000
900,000	$68,000
1.2e+06	$128,000
1.5e+06	$188,000
1.8e+06	$248,000
2.4e+06	$368,000

How to read the result

A positive AFN is the funding gap to cover with debt, equity or slower growth. Higher capital intensity raises it; a higher margin or lower payout lowers it. Growth far above the zero-AFN rate means outside finance every year.

Common mistakes

Including bank loans or bonds in spontaneous liabilities; those are the financing choices.
Counting all assets when the firm has spare capacity; idle assets need not grow.
Using the margin on last year's sales instead of next year's sales for retained earnings.
Treating the result as exact; ratios rarely stay perfectly constant.

Keep in mind: The percent-of-sales method is a simplified forecast. Real financing needs depend on timing, seasonality and lumpy investments. Not financial advice.

Frequently asked questions

What does a negative AFN mean?

Internally generated funds exceed what growth requires, so the firm has surplus funds to pay down debt or return to owners.

How can a company reduce its AFN?

Raise the profit margin, retain more earnings, use assets more efficiently, or negotiate longer supplier credit.

Is the zero-AFN growth rate the same as the sustainable growth rate?

No. The sustainable growth rate allows debt to grow to keep leverage constant; the zero-AFN rate uses no new external funds at all.

Sources: K. S. Bigel, Introduction to Financial Analysis, section 9.6 "The EFN Formula Explained" (Business LibreTexts, CC BY 4.0)

Checked 9 Nov 2026. External/additional funds needed formula EFN = (A₀/S₀)ΔS − (AP₀/S₀)ΔS − M₀S₁RR₀: K. S. Bigel, “Introduction to Financial Analysis”, section 9.6 “The EFN Formula Explained” (Business LibreTexts, CC BY 4.0). Zero-AFN growth rate: algebra on the same formula.

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