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A 28-day recharge renews more often than a calendar-month plan. Compare annualised cost, inclusions, introductory periods and device compatibility before deciding which is cheaper for your needs. If you want to keep your number, organise the transfer with the new provider while the number is active and confirm the account details and timing. Porting a number does not erase a final bill, handset balance or other contractual obligation. The examples here use fictional prices, not live offers.
The price label is only half the comparison
A plan advertised at $30 every 28 days is not the same annual commitment as $30 per calendar month. Both can look like a “monthly” phone bill when you scan a list, but the renewal dates move differently. That affects the annual cost and the weeks in which money leaves your account.
Before comparing, record the price, renewal period, introductory conditions, data allowance, speed restrictions, coverage, expiry and any separate handset repayment. Then read the plan’s Critical Information Summary and relevant terms. A familiar brand name or a large data number is not enough to establish value.
Use actual needs as the starting point. If you need reliable calls at home and on a regular regional route, a cheaper data-heavy offer may solve the wrong problem. The lowest entered price is only useful among services that meet the requirements you have verified.
Convert 28 days to an annual planning equivalent
For a planning estimate, multiply the recharge price by 365 divided by 28. A fictional $30 recharge gives about $391.07 across a 365-day annualised period. A $30 calendar-month plan gives $360 over twelve unchanged monthly payments. The difference is about $31.07 under those assumptions.
That fractional-recharge result is an annualised comparison, not a promise of exactly $391.07 being debited in a particular calendar year. Actual payment dates and whether a recharge falls just inside or outside the period affect cash flow. Keep the renewal calendar as well as the annual average.
For monthly budgeting, divide the annualised 28-day cost by twelve: about $32.59 in this example. Do not enter $30 as the calendar-month equivalent simply because it is the number on the recharge. Cognivo’s recurring-cost tool can make the frequency visible before you compare two offers.
| Billing period | Annualised cost | Monthly average |
|---|---|---|
| Every 28 days | $391.07 | $32.59 |
| Each calendar month | $360.00 | $30.00 |
Introductory prices need an expiry date
A low first recharge or discounted opening period can distort a comparison if you multiply it across the whole year. Record exactly how many renewals or months receive the introductory price, then apply the ongoing price to the remaining period.
Consider a fictional calendar-month plan at $20 for three months and $35 for nine months. Its twelve-month cost is $375 before any other charge. A different $31 monthly plan would total $372 across twelve unchanged payments. The first offer has a lower headline but a slightly higher entered annual total.
A small cost difference may be outweighed by coverage, support or inclusions. Keep the arithmetic separate from the service decision. If the price can change, describe the comparison as based on the written terms checked on a particular date rather than a guaranteed bill for the coming year.
Read the Critical Information Summary with a purpose
ACMA says telcos must provide a Critical Information Summary for their products, services and plans. Use it to answer concrete questions: what is included, what costs extra, what restrictions apply and what happens when an allowance is exhausted. Keep the document or a dated copy with the offer.
Then check the conditions that matter to your household. International calls, roaming, data rollover, hotspot use, speed caps and expiry can alter the practical value. A rollover benefit you never use may have little value; an excluded call destination you use often can matter a great deal.
Do not assume the CIS contains every circumstance you care about. Ask the provider to confirm any ambiguity, especially bundled discounts, linked services or a handset agreement. The point is a comparable set of confirmed facts, not a large spreadsheet filled with guesses.
Confirm coverage and device compatibility before switching
ACMA’s mobile-service guidance recommends checking coverage and confirming an existing device will work on the new network. Its guidance also notes the requirement that a service cannot be provided through a device that does not support Triple Zero calls. Do not rely on a phone displaying a signal as proof of complete compatibility.
Ask the provider about your exact device model and the service you intend to buy. Check the locations you actually use, including home, work and regular travel. Network names and reseller arrangements do not remove the need to inspect the particular offer’s coverage information and restrictions.
Where available and practical, consider a way to test suitability without making a large commitment. Understand the conditions first; do not assume a universal change-of-mind or cooling-off right applies to every ordinary online telco purchase. Ask what happens if the service does not work as represented.
Keep the number active while organising the port
ACMA says you can usually keep an Australian mobile number when switching, including a prepaid number, and that only active numbers can be ported. A suspended number can still be active, but contractual obligations remain. Arrange the process with the new provider rather than cancelling first and hoping to recover the number later.
Check the name and account details held by the current provider, then ask the new provider what it needs for authentication. Follow the legitimate identity-check process. Never give a one-time code to an unexpected caller claiming that your transfer needs rescuing.
Choose a practical transfer time and ask what interruption to expect. If the number is your main account-recovery channel, make sure you can still reach critical services through a trusted method. Avoid starting the switch immediately before travel, an urgent appointment or another situation where a short interruption would be difficult.
Source: ACMA: keep or port your number
The old account may still have a final balance
ACMA explains that porting does not remove the need to pay final bills and relevant contract obligations. A handset balance, early-termination question or another linked service can remain even after the mobile number moves. Ask the old provider for a clear final account position.
Check whether a bundle discount on another household service changes when the mobile leaves. Record any confirmed effect in the comparison. A $5 monthly phone saving can be outweighed by a separate discount ending elsewhere, but only include that if the terms actually apply to you.
Keep the old account accessible until the final bill is checked and any credit or dispute is settled. A successful port proves the number moved; it does not prove every account balance is zero. Cancel only the additional services you actually intend to end and confirm their own process.
If a transfer fails or happens without permission
Contact the relevant telco through its official channel and explain whether this is a failed authorised port or a transfer you did not authorise. Those are different problems. Retain the request confirmation, dates, reference numbers and any interruption details.
ACMA’s number-porting guidance directs unresolved complaints to the Telecommunications Industry Ombudsman after the telco complaint. Follow the current process and identify the outcome you want: restoration, completion, correction of a charge or investigation of an unauthorised change.
If an unexpected loss of service coincides with account alerts or suspicious financial activity, contact affected institutions promptly. Do not treat every outage as a scam, but do not ignore the possibility when the surrounding evidence is concerning. Use independently verified contact details rather than the messages claiming to fix it.
Sources: ACMA: keep or port your number · ACMA: switch phone or internet provider
A switching checklist that does not stop at activation
Before switching, save the current terms, identify the number’s account holder, confirm device compatibility and compare the total cost over the same period. Include any handset or bundle consequences. Keep the number active and follow the new provider’s transfer instructions.
After activation, test the functions you depend on and check account-recovery access. Confirm the new renewal period and ongoing price. Review the old final bill and keep any unresolved amount separate from the future savings calculation.
Cognivo’s comparison tool uses entered calendar-month equivalents. It does not fetch live prices, check coverage, authenticate a port or cancel a service. Use the recurring-cost tool for the 28-day conversion first, then enter verified comparable amounts and record the offer’s checked date.
FAQ: Is a 28-day plan always worse value?
No. It renews more often than a calendar-month plan, so compare the annualised cost correctly. A lower recharge price or useful inclusions may still make it suitable. Coverage, compatibility and actual usage matter as well. The frequency correction prevents a misleading comparison; it does not rank every prepaid plan below every monthly plan.
FAQ: How many 28-day recharges are there in a year?
A 365-day annualised period contains about 13.04 lots of 28 days. Actual debit counts depend on the start date and the period examined. Use the annualised figure to compare ongoing cost and a dated calendar to manage cash flow. Do not confuse the two views.
FAQ: Should I cancel the old mobile service before transferring?
If you want to keep the number, organise the port while it remains active and follow the providers’ instructions. ACMA says only active numbers can be ported. Confirm any remaining contract and handset questions separately. Cancelling first can turn a routine transfer into a recovery problem.
FAQ: Does porting remove the old handset debt?
No such assumption is safe. Ask the provider for the remaining handset and account obligations, and read the agreement. A number transfer is a service change, not proof that every amount has been paid. Include confirmed remaining costs in your switching decision and check the final bill after the port.
Put the next step into practice
Use your own confirmed figures and keep outstanding questions visible. Core tools are free, with no bank connection or compulsory account.
Open the Compare two bills ↗Sources and editorial notes
Sources checked 23 October 2026. Worked examples are fictional illustrations. Rules, eligibility and product terms can change; use the official source for your circumstances.
- ACMA: choose your mobile service carefully ↗
- ACMA: Critical Information Summaries ↗
- ACMA: keep or port your number ↗
- ACMA: switch phone or internet provider ↗
General information, not an individual financial or legal assessment. AI-assisted drafting with source checks; independent professional review has not been completed. How we prepare our guides · Suggest a correction