Billing

This page explains how an invoice is made, so you can recompute any line of it yourself. Your own rates are on Organisation → Billing → Your rates; your invoices are on Organisation → Billing.

How your bill is made

You get one invoice a month, on your billing day (UTC). It covers whole billing months, up to the start of that day: a billing month runs from one billing day to the next, so every invoice rates a month whole.

One line per resource. Each server, database, domain, service, custom metric and log source has its own line, with the hours it was billed (or the GB, for logs). A line that comes to 0.00 is still listed.
Resources are billed for the hours they are monitored. Logs are billed by the GB.
A volume discount, if you earned one, is one extra line per resource type, after the resource lines. See volume bands.
Data delivered late is billed in the hour it was collected, unless that hour falls in a billing month that has already been invoiced. A late hour in an invoiced month is billed on your next invoice, in its own month, alone.
Two invoices on one day happen only when your price list changes to one priced in another currency and the invoice covers months on both lists: you get one invoice per currency, each converted on its own. See currencies and exchange rates.

While a billing month is under way, Organisation → Billing shows it as Current period (in progress): an estimate of the next invoice, which uses the latest exchange rate and says so.

Your price list

Every organisation has one price list, shown under Organisation → Billing → Your rates: each resource type, its monthly price and its volume bands, in your billing currency.

New organisations get the current price list.
Your list does not change when a newer list is published. WatchTower15 moves an organisation to another list only by assigning it, and never inside a billing month.
A change to your list is shown in advance on Your rates (Your rates change on …), with a switch to view the new rates, and it starts on a billing day.
A list made for one organisation shows its own name on Your rates.

If your organisation has no price list yet, Your rates says they are being set up, and the current period shows no amounts until they are in place.

What counts

Resource	One unit is	Which hours count
Servers	One approved server.	Each hour its monitoring is on. Paused hours, archived servers, servers waiting in Pending and deleted servers are not billed.
Database instances	One database (every schema on it is included).	Each hour a collector reported it. Draft and paused hours are never billed. See databases.
Domains	One domain.	Each hour it is active. Paused hours are not billed.
Services	One service.	Each hour it was checked. A service checked once a day bills only the hours it was checked.
Custom metrics	One metric.	Each hour the metric exists, however often you send to it. See custom metrics.
Log ingest	One GB of log content.	The log content you send, from your servers and your log sources together. See log ingest.

Volume bands

Every resource type has volume bands: the more of a type you monitor, the less each extra one costs. The bands are graduated: a band’s discount applies only to the units inside that band, so adding a resource never lowers your bill. Bands are per resource type and per organisation: 20 servers and 20 domains each fill their own.

An example on the current standard list, where servers cost $17 a month and the second band (servers 16 to 30) is 10% off, $15.30:

20 servers monitored all month cost 15 × $17.00 + 5 × $15.30 = $331.50.

On the invoice that is 20 lines of $17.00 (the first band’s price), less one line, Volume discount — Servers, of −$8.50 (5 × ($17.00 − $15.30)): $340.00 − $8.50 = $331.50.

Each type has its own bands; Your rates lists them all, with the discount of each band.

Bands use your average over the month

The bands are filled by hours, not by a count on one day. A band’s allowance is its size times the hours in the billing month, so the bands follow your average number of resources over the month, and a resource monitored part of the month fills them by its hours.

An example, 15 servers all month plus 10 more for the last 10 days of a 30-day month:

Hours: 15 × 720 + 10 × 240 = 13,200 hours, against a first-band allowance of 15 × 720 = 10,800 hours.
Graduated: 10,800 hours at $17.00 ÷ 720 and 2,400 hours at $15.30 ÷ 720: $255.00 + $51.00 = $306.00. That is the average number of servers over the month, priced on the bands.
On the invoice: 15 lines of $17.00 and 10 lines of $5.67 (240 × $17.00 ÷ 720 = $5.666…), $311.70, less one discount line of −$5.67 (2,400 × ($17.00 − $15.30) ÷ 720 = $5.666…): $306.03.

The invoice is three cents more than the graduated figure because each line is rounded to the cent on its own. See rounding.

Months of different lengths

A resource monitored all month costs its monthly price, whatever the month’s length: the same in February as in a 31-day month. A part month costs its share of the hours.

An older price list may still bill by the hour at the monthly price ÷ 720, so a 31-day month costs about 3.3% more than a 30-day one on it. Your rates says which applies to you.

Log ingest

Logs are billed by the GB of message content only: not timestamps, labels or wrappers, and 1 GB is 1,000,000,000 bytes. They have volume bands too, measured in the GB ingested in the billing month, from your servers and your log sources together.

Currencies and exchange rates

Prices are set in US dollars. If your organisation is billed in pounds sterling (GBP) or euros (EUR), your invoices are converted:

at the European Central Bank reference rate of the invoice date: the ratio of the ECB’s two euro rates for that day, rounded to 6 decimals, printed on the invoice with its date;
line by line: each line’s dollar amount is rounded to the cent, then converted and rounded to the cent. The invoice total is the sum of its lines;
the invoice also says what it was converted from, and the conversion appears on the invoice PDF and in the invoice email.

An example, at a rate of 0.750156 pounds to the dollar: a $17.00 line is £12.75 (17.00 × 0.750156 = 12.752652), and a −$8.50 discount is −£6.38.

The estimates in the app (the price cards, Your rates and the current period) use the latest rate we hold and say which; an invoice uses the rate of its own date. If no rate is stored yet, an estimate is shown in dollars, and says so.

Rounding

Every amount is computed exactly, as you would get it by hand, and each line is rounded to the cent once, half a cent rounding up. A service monitored 715 hours at £0.007 an hour is exactly £5.005, so its line is £5.01. The volume discount is one line per resource type, rounded the same way, and a converted line is rounded the same way.

A worked invoice with every figure recomputable: the part-month example above, in dollars, 15 × $17.00 + 10 × $5.67 − $5.67 = $306.03. Converted at 0.750156, each line converts on its own: $17.00 is £12.75, $5.67 is £4.25 (5.67 × 0.750156 = 4.253…) and the −$5.67 discount is −£4.25, so the invoice is 15 × £12.75 + 10 × £4.25 − £4.25 = £229.50. Converting the $306.03 total in one go would give £229.57: the invoice is the sum of its converted lines, which you can recompute from the printed dollar amounts and the printed rate.

Changing your billing currency

Your billing currency is USD, GBP or EUR, set under Organisation → Billing → Billing Details. You can change it until your first invoice; after that it is fixed.

Euro invoices are paid by card only. An organisation billed in euros cannot choose Invoice / bank transfer under Payment Details, and an organisation that pays by bank transfer cannot switch to euros.
Your price list keeps its own currency: a list priced in dollars is converted into your new currency, at the rates above.

Courtesy accounts, limits and VAT

A courtesy account has its usage covered by WatchTower15; its invoices are listed in full and nothing is charged.
Account limits cap what you can add; they are not prices.
VAT or GST is added where it applies, and your VAT/GST number is under Organisation → Billing → Billing Details.

Account limits & courtesy accounts — limits, courtesy accounts and the payment method.
Custom metrics — what a metric costs.
Databases — when a database is billed.
Getting started — your billing currency.
Roles & permissions — billing.view and billing.edit.