Entering formulas in BfX

Locale

The screenshots on this website have been made on computers having a Dutch locale. In Dutch (and many other European countries), a comma is used as a decimal separator (e.g., 2,3), whereas the UK, US, and many other regions use a dot (2.3). This impacts how formulas in Excel cells are displayed and entered.

In our examples, arguments in cell formulas are separated with semicolons (;) and decimals with a comma (,). On computers configured with a US/UK locale, you typically use a comma (,) as a parameter separator and a dot (.) for decimals:

• =bfx_d(740;40;0,5) (Netherlands and other European countries)
• =bfx_d(740,30,0.5) (UK, US, AU, ...)

Please be aware that BfX does not switch between Imperial and metric (SI) units automatically; this must be done explicitly in every cell (see below). Note also that in Visual Basic for Applications (VBA) code, a dot (.) is always used as the decimal separator regardless of your local Windows settings.

The International System of Units (SI) and Imperial Units

If not specified otherwise for every number you put into a formula cell, BfX treats the value as belonging to the International System of Units (SI). There is one exception: the ballistic coefficient is always expected in Imperial units [lbs/inch²]. However, BfX fully supports many other Imperial units as well.

Entering formulas in Excel cells

The following picture illustrates how BfX works in Excel:

BfX_Zx calculates the path height at a specific downrange distance. In cell E3, entering the formula =BfX_Zx() without arguments prompts BfX to return the function signature and help text:

height_at_x = BfX_Zx(v0; s; h; zx; x; c) [m] or converted to angle

Where:

• v0 [m/s] is the muzzle velocity
• s [m] is the height of the line of sight above the muzzle
• h [m] (usually 0) is the height of impact at distance zx
• zx [m] is the distance where the impact is known (e.g., the scope zero distance)
• x [m] is the distance at which we want to know the path height
• c is the G1 ballistic coefficient in [lb/inch²] to be used with the Pejsa drag function
• height_at_x is then calculated in [m]

As mentioned, default units belong to the International System of Units (SI). However, you can change the units of individual variables. Rows 1 and 2 in the image above demonstrate BfX_Zx with parameters specified in cells F1:R1 and F2:R2. To change the output unit, specify it as the first argument: in the picture above, this is "cm" in cell F1 and "moa" in cell F2, converting the path height (-153.7 cm) into minutes of angle.

To specify an input unit, append it directly behind the value, such as 200 [yd]. Ballistic coefficients in [kg/m²] are not accepted; hence, the ballistic coefficient c can only be followed by its drag function identifier.

Built-in Help Functions

BfX supplies extensive help directly within Excel: =BfX_Help(n) (with n = 0, 1, ..., 130) provides general function help (click here for a listing). Similarly, =BfX_Help2(n) (with n = 0, 1, ..., 100) lists all supported units and drag functions (click here for details).

It is not necessary to specify default arguments; you can omit them from the argument list of BfX functions where defaults apply.