Taxes and discounts
Tax rates
Set up the rates you charge once, then apply them where they're needed. A rate has a Name and a Rate (%): "VAT 20%", "Sales tax 8.875%". The rate has to be above 0 and below 100.
Give them names a client will understand, since the name appears on the invoice.
Manage them under Payments → Settings → Tax Rates.
Applying tax
Tax is applied per line, so an invoice can mix taxed and untaxed items. Useful where, say, a service is taxed and an expense you pass on isn't.
You can also attach a tax rate to a booking service, so the invoices those bookings create carry the right tax without you thinking about it. See Pricing and deposits.
Tax inclusive or on top
Each rate has a Price includes tax switch.
Off (the usual setting) means tax is added on top of the price you entered. A $100 line at 20% bills the client $120.
On means the price you entered already contains the tax. A $100 line at 20% bills the client $100, of which $16.67 is tax.
Get this wrong and you either undercharge by the tax amount or bill more than you quoted, so check it when you create a rate.
Set as default applies a rate automatically to new line items.
Deleting a rate
Deleting a rate doesn't disturb invoices that used it: each line keeps the rate it was created with. Services and add-ons that used it simply stop applying tax, so check your services after removing one.
Discounts
An invoice can carry one discount, added with + Add Discount under the totals. Choose Percentage (%) or Fixed Amount, enter the value, and add a description. The link disappears once a discount exists. To add a different one, remove it with the small cross beside it.
A percentage can't exceed 100%, and a fixed amount can't exceed the invoice subtotal, so a total never goes negative. A full 100% discount is allowed, which is how you issue a complimentary invoice that still reads as a real document.
Description (optional) is worth filling in. "Returning client, 10%" reads better than an unexplained reduction, and it's the kind of thing you want on the record when the same client expects it again next year.
One discount per invoice is deliberate. If you need to reduce two things separately, adjust the line prices instead. That's clearer for the client anyway.
How the total is worked out
Lines are added up, then tax is calculated on each line's full price, then the discount comes off the total.
A discount does not reduce the tax. If you discount a $1,000 invoice by $100, the tax is still calculated on $1,000. That's the standard accounting treatment, but it does surprise people who expect the discount to come off first.
Each line is rounded on its own, and the totals add up those rounded lines. So the figures on the invoice always add up to the total the client is asked for.
What CoreHue won't do
It won't tell you what tax to charge, work out your obligations, or file anything. It applies the rates you tell it to and keeps a record.
For anything beyond that, talk to an accountant. Tax rules vary by country and by the kind of work you do, and getting it wrong is expensive in a way that a support page can't fix.