Actual costs and the run-rate · Finance Platform

What the business really spent per month and category, and the monthly run-rate a plan starts from (ADR 80, workflow). Calculated by the engine (calc/actual_costs.py, model actual-costs-1.0.0).

What the business really spent per month and category, and the monthly run-rate a plan starts from (ADR 80, workflow). Calculated by the engine (calc/actual_costs.py, model actual-costs-1.0.0).

The example

Three months, July to September 2026, in euros:

Expense	Category	Paid (gross)	Net	Service period
Hosting, 3 Jul, 3 Aug, 3 Sep	cloud hosting (cost of sales)	119.00, 119.00, 142.80	100.00, 100.00, 120.00	the month
Annual software licence, 1 Jul	software	1,428.00 at 19 % VAT	not stated	Jul 2026 to Jun 2027
Tax adviser, 20 Aug, marked one-off	professional services	595.00	500.00	the month

1. Amount on the chosen basis

a_r = \begin{cases} \text{net}_r & \text{basis net, net known} \\ \dfrac{\text{gross}_r}{1 + v_r} & \text{basis net, net unknown, rate known (estimated)} \\ \text{gross}_r & \text{otherwise} \end{cases}

Symbol	Meaning	Unit
a_r	Amount of expense r used in the table	base currency
\text{net}_r, \text{gross}_r	Net and gross amount, converted with the expense's FX rate	base currency
v_r	VAT rate	fraction

In plain words. On a net basis the amount without VAT is used; when only the gross amount and the rate are known it is estimated and the warning net_estimated is shown. Example. The licence: 1428 / 1.19 = 1200.

2. Spreading over the service period

C_{k,m} = \sum_{r \in k} \frac{a_r}{|S_r|}\,[m \in S_r]

Symbol	Meaning	Unit
C_{k,m}	Cost of category k in month m	base currency
S_r	The months of the expense's service period; without one, the month of its date	months

In plain words. An expense for several months is shared evenly over them; an expense for one month counts in that month. Example. The licence adds 1200 / 12 = 100 to software in every month from July to June.

3. Run-rate per category and in total

\bar C_k = \frac{1}{n}\sum_{m=1}^{n}\left(C_{k,m} - O_{k,m}\right) \quad\text{(average)},\qquad \bar C_k = C_{k,n} - O_{k,n} \quad\text{(last month)},\qquad \bar C = \sum_k \bar C_k

Symbol	Meaning	Unit
n	Months in the window (at most 36)	months
O_{k,m}	Part of C_{k,m} from expenses marked one-off	base currency
\bar C_k, \bar C	Monthly run-rate of category k, and of all categories	base currency per month

In plain words. The run-rate is what a normal month costs: the average of the window (a month with no costs counts as zero and is flagged no_costs_in_<month>) or the last month, without one-off expenses. Categories whose line is cogs.* add up to the cost-of-sales run-rate, the rest to operating costs.

Example. Hosting \frac{100 + 100 + 120}{3} = 106.67; software 100; the tax adviser is one-off, so 0. Total \bar C = 106.67 + 0 + 100 = 206.67 a month, of which 106.67 is cost of sales. The window's total including the one-off is 1120.00.

For developers: actual_costs, ActualCostsRequest, ActualCostsResult; test test_actual_costs.py.