isbaremetal

How traffic gets billed.
Three models, one without a meter.

A hosting invoice turns traffic into money in one of three ways: a monthly allowance in terabytes, the 95th percentile of your rate, or the size of the port. Here is how each one is counted, with arithmetic you can check on paper, and where each one bites.

1 Gbps
324 TB a month
samples
8,640 a month
95th pct
36 free hours
ours
the port, no counter

From gigabits to terabytes.

Ports are sold in bits per second. Allowances are sold in bytes per month. Two steps get you from one to the other: eight bits make a byte, and a 30-day month has 2,592,000 seconds.

So 1 Gbps is 125 megabytes a second, 10.8 terabytes a day and 324 terabytes a month if the port runs at line rate the whole time. The table below does the same sum for every port we sell.

What a port moves in a monthgbps → tb

Line rate times thirty days. Decimal terabytes, the way hosts and clouds count them.

per month324 TB
per day10.8 TB
1 TB takes2 h 13 min
portper secondper dayper 30-day month1 TB takes
1 Gbps125 MB10.8 TB324 TB2 h 13 min
10 Gbps1,250 MB108 TB3,240 TB13 min
25 Gbps3,125 MB270 TB8,100 TB5 min
40 Gbps5,000 MB432 TB12,960 TB3 min
100 Gbps12,500 MB1,080 TB32,400 TB1 min

Decimal units throughout: a terabyte is 10¹² bytes, the way hosts and clouds bill. Your OS may show binary TiB, about 9% larger per unit, so the same transfer looks smaller there.

Unmetered, not unmeasured.

Nothing bills your traffic here, but it is still there to see: on the traffic graph of your port and in tools on the server itself. Graphs are drawn the same way everywhere, so the numbers on them mean the same thing too.

a point
the average rate over 5 minutes, not the fastest second in them
out · in
out is what your server sends, in is what it receives
average
times the hours in the month, it is your volume in TB
95th percentile
often drawn as a line; on a metered plan it is the bill
one month on a 1 Gbps portexample profile
average
208 Mbps
moved this month
67.4 TB
95th percentile
332 Mbps
peak
850 Mbps
24 hours fit inside the 36 discarded hours, so the 95th percentile ignores the burst. On a metered plan that line would be the bill. On ours it is a number on a graph.

The transfer allowance.

The plan includes a number of terabytes a month. Some hosts count outbound traffic only, others both directions. Under the line the invoice does not move. Over it, usually one of two things happens: every extra gigabyte is billed at an overage rate, or the port is slowed down until the month resets.

The allowance, not the port, is the real limit. A 1 Gbps port can move 324 TB in a month, so any allowance below that runs out before the month does if the port is kept busy. The question to ask is how many days of full speed the plan pays for.

counted
bytes moved in the month
over the line
overage per GB, or a slower port
suits
steady traffic well under the allowance
bites
a launch, a release day, a video that spreads

The 95th percentile.

Here you pay for a rate, not a volume. The host reads your port every 5 minutes: 8,640 samples in a 30-day month. At the end of the month it sorts them, drops the highest 5%, which is 432 samples, and bills the highest one left, usually as a price per Mbps.

Those 432 samples add up to 36 hours. Bursts that fit inside them, in total across the month, cost nothing. A burst that runs longer stops being dropped: it becomes the rate the whole month is billed at, quiet days included.

suits
a quiet baseline with short, rare peaks
bites
peaks that last days, or a baseline that keeps rising
Which burst is free, and which is not95th percentile

Billing by percentile throws away the busiest 5% of samples. That rule decides your invoice.

samples a month8,640 · every 5 min
discardedtop 5% · 36 hours
billed at100 Mbps

A burst that short falls inside the discarded 5%, so it costs nothing; the invoice is written by the quiet 100 Mbps instead. Two levels simplify a real profile: this shows the mechanism, not anyone’s bill.

The port, and nothing counting it.

You pay for the size of the port: 1, 10, 25, 40 or 100 Gbps. Nothing measures how much went through it or how fast, for billing. Run it at line rate every hour of the month and the invoice is the same as in a quiet month. The Start plan, for example, is $99 a month on a 1 Gbps unmetered port, whether it moves 1 TB or 324.

Unmetered is not unlimited. The port is the limit: 1 Gbps moves at most 1 Gbps. Behind the port the uplink is shared, and if it ever fills at a peak, traffic on it is managed evenly for everyone until the peak passes. It is not a cap and it never reaches the invoice. Section 3 of the terms →

counted
nothing
allowance
none
percentile
none
fair-use clause
none
you pay for
the port size, flat monthly
suits
sustained egress, big releases, traffic you cannot forecast

Three models, one table.

modelwhat is countedinvoice followsa short bursta full month at line rate
transfer allowancebytes moved in the monthvolumefree until the allowance runs outoverage per GB, or a throttled port
95th percentileport rate, every 5 minyour 95th-percentile ratefree up to 36 h a monthbilled at the burst rate
port · oursnothingthe port sizeno counterno counter

The short answers.

  1. 01

    How many terabytes is 1 Gbps per month?

    324 TB over a 30-day month at line rate: 1 Gbps is 125 megabytes a second, times 2,592,000 seconds. A 10 Gbps port moves 3,240 TB. These are decimal terabytes, the unit hosts bill in.

  2. 02

    What is 95th percentile billing?

    The host samples your port rate every 5 minutes, 8,640 times a month, throws away the highest 5% and bills the highest sample that is left. You pay for a rate in Mbps, not for a volume in terabytes.

  3. 03

    How long can I burst under 95th percentile billing?

    36 hours in a 30-day month, in total. That is 5% of 720 hours, or 432 discarded samples. A burst that runs longer stops being discarded and sets the rate for the whole month.

  4. 04

    Is unmetered the same as unlimited?

    No. Unmetered means nothing counts your volume or bills your rate. The limit is the port itself: a 1 Gbps port moves at most 1 Gbps. Behind the port the uplink is shared, and section 3 of our terms says what happens at a rare full-uplink peak.

  5. 05

    Why do hosts count in TB and not TiB?

    Billing uses decimal units: a terabyte is 10¹² bytes. Operating systems often show binary tebibytes (2⁴⁰ bytes), which are about 9% larger, so the same transfer looks smaller in your OS than on an invoice.