How is the projected usage worked out?

It takes your usage so far, divides by the days elapsed to get an average daily run-rate, then multiplies by the total days in the cycle. If that projected total is above your cap, the tool shows how much you would go over.

What is the safe daily allowance?

It is the remaining data divided by the number of days left in the cycle. Staying at or below that daily figure keeps you within your cap for the rest of the month.

Why use 1 GB = 1000 MB instead of 1024?

ISPs and mobile carriers quote data caps in decimal gigabytes, where 1 GB = 1000 MB. The calculator matches that convention so the remaining figure lines up with the number on your bill or carrier app rather than the binary (1024) value an operating system might show.

What happens if I am only one day into the cycle?

The projection still works, but it is very sensitive early on — one heavy day makes the projected total look alarming. The estimate becomes reliable as more of the cycle elapses, because the average is based on more days of real usage.

Does it work for mobile data as well as broadband?

Yes. Enter any monthly allowance in GB — a mobile plan, a home broadband cap or a mobile hotspot bucket — and the same run-rate maths projects whether you will finish the cycle within the limit.

Is my usage data sent anywhere?

No. The calculator is privacy-first and runs entirely in your browser — the numbers you enter never leave your device.

Data Cap Usage Calculator

Stay ahead of a monthly data cap by turning the data you have used so far into a run-rate projection for the whole billing cycle. It is for anyone on a capped mobile plan, home broadband allowance or hotspot bucket who wants to avoid overage charges or throttling before the cycle ends.

How it works

The calculator runs four quick steps from your inputs (cap, used, day of cycle, days in cycle):

Remaining = cap − used, and percentage used = used ÷ cap × 100
Daily run-rate = used ÷ days elapsed
Projected cycle total = run-rate × total days in the cycle
Safe daily allowance = remaining ÷ days left in the cycle

If the projected total is above your cap, it shows exactly how many GB over you are heading. Units are decimal (1 GB = 1000 MB), matching how providers quote allowances.

Example

A 100 GB plan, 45 GB used by day 12 of a 30-day cycle:

Remaining = 100 − 45 = 55 GB (45% used)
Run-rate = 45 ÷ 12 = 3.75 GB/day
Projected = 3.75 × 30 = 112.5 GB → over cap by 12.5 GB
Safe daily = 55 ÷ (30 − 12) = 3.06 GB/day to finish on cap

Metric	Value
Remaining	55 GB (45% used)
Run-rate	3.75 GB/day
Projected total	112.5 GB
Over cap by	12.5 GB
Safe daily allowance	3.06 GB/day

Everything is calculated locally in your browser, with nothing sent anywhere.