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joeu2004 joeu2004 is offline
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Default Need formula to calculate subtotal before sales tax

On Sep 13, 8:48 pm, HLR2007 wrote:
I have a spreadsheet showing a year's worth of invoices that have the
final totals listed, but I need a formula to show the subtotal before
the sales tax is added.
[....]
The example I am working from [....]
Subtotal of Order = $253
Sales Tax = 8.75%
Final Total = $275.14


Ostensibly, if the final total is in B3 and the sales tax rate in B2,
then subtotal in B1 can be computed by:

=round(B3/(1+B2), 2)

But I don't know if that will always reproduce the original subtotal
exactly. You see, originally the final total (B3) was computed
effectively by:

=B1 + round(B1*B2, 2)

But it seems to work for all the (random) numbers that I have tried.