How to set up conditional call forwarding (codes by carrier)

What conditional call forwarding is

Your phone rings. If you pick up, nothing else happens. If you do not, the call carries on to a second number you chose, and the caller hears ringing the whole time. That is conditional forwarding: the call only moves when a condition is met.

It is different from the forwarding most people know, where every call skips your phone and goes straight to the other number. For a business that is the wrong tool, because you still want to answer when you can. You just want the ones you cannot answer to go somewhere better than voicemail.

Where they go is up to you: a second person, an office line, after-hours call answering, or an AI receptionist. The forwarding is the same either way. If the reason you miss calls is that you are on the tools, our page on answering business calls when you're busy on a job covers what to forward to.

Busy, no answer, unreachable

Carriers split "you did not answer" into three conditions, and each one can be set separately.

• Busy: you are already on a call. Without forwarding, the second caller goes to voicemail while you are talking to the first.
• No answer: the phone rang and nobody picked up. Most carriers let you set how long it rings first, and a short delay is the difference between a caller who waits and one who hangs up.
• Unreachable: the phone is off, in airplane mode, or out of signal. A basement, a crawl space, or the far side of a job site.

For a service business, set all three to the same number. A missed call is a missed call whichever way it was missed.

Codes for Verizon, AT&T and T-Mobile

Dial these on the phone whose calls you want to forward, as if you were making a call. Each row links the carrier page it was read from on September 28, 2026; check that page before you dial, because carriers do change them.

AT&T has no row because AT&T's wireless support page publishes no codes. It says forwarding is set from the phone itself, cannot be managed online, and points to its device tutorials, so on AT&T use the phone's own call settings and run the test below.

Two things the other pages say that are easy to miss. Verizon's page lists *71 for unanswered calls and *72 for all calls, and does not list separate busy or unreachable codes. T-Mobile's page lets you set the ring time before a no-reply call forwards, from 5 to 30 seconds, by adding two asterisks and the seconds before the final # on the no-reply code.

Landlines and VoIP phone systems

An office landline usually has its own forwarding codes from the phone company, and a VoIP system (the kind with an admin login) has forwarding settings in that login rather than on the handset. Look for "forward on no answer" or "forward when busy" in the call-handling section, and set the ring count there.

We are not listing landline or VoIP codes here because they vary by provider and the wrong code on a business line can forward everything. Use your provider's page, and run the test below before you rely on it.

Test it in two minutes

1. Dial the code for no answer with the number you want to forward to.
2. From a second phone, call your business number and let it ring out.
3. Confirm it lands on the forwarding number and that whoever answers says your business name.
4. For busy: be on a call, then call yourself from the second phone. For unreachable: put the phone in airplane mode and call it.

If the second phone hears voicemail instead, the code did not take. Dial the turn-off code, then try again, and check the carrier page for a note about your plan.

How to turn it off

Use the turn-off code in the table on the same phone. On T-Mobile, ##004# resets every kind of forwarding to the default in one dial, which is the quickest way out if you are not sure which conditions you set. On Verizon, *73 turns forwarding off and the page says you should hear a confirmation tone or message.

Turning it off is worth practising once, because you will want it the day the forwarding target changes.

Why forwarding beats porting your number

Some services ask you to move your number to them. Then the number lives with the service, every call goes through them first, and leaving means moving it again.

Forwarding keeps the number with you. Your phone still rings first, the service only sees the calls you miss, and if you stop using them you dial one code and it is over. That is how we set up missed-call text-back: you dial the forwarding code on your business phone, and the number stays yours. Our article on keeping your phone number with an answering service goes through the porting question in full, and if you are working out whether the missed calls are worth all this, start with what missed calls cost a service business or, if you are in the trade, our page on HVAC missed calls.