How do I forward only the calls I can’t answer?

Use conditional call forwarding, often called no-answer forwarding. Your phone rings as usual; if nobody picks up within a set time, or the line is busy or switched off, the call moves to a second number you choose — a coworker, a backup line or an answering service. On a regular cell line you turn it on with a short dialing code. On an internet-based business phone system, or an app like Google Voice, you set it in an app or web portal instead. Either way, make a test call before you trust it.

How long it rings before it forwards

This is the setting that matters most, and it varies by carrier. For AT&T and T-Mobile lines, a third-party table of carrier codes puts the default wait at about 20 seconds — roughly four to five rings — and says it can often be shortened to about 15 by adding a timer to the code. Verizon’s ring count generally isn’t adjustable. Set it too short and calls you could have grabbed go to backup; too long and the caller gives up before backup ever hears it. Pick the shortest wait that still lets you reach the phone on a normal day.

The codes, carrier by carrier

These are the common codes. Check with your carrier and make a test call — plans, phones and carriers’ own rules differ.

• Verizon: *71 followed by the number you’re forwarding to sends only the calls you don’t answer; *72 forwards every call; *73 turns forwarding off. Verizon says forwarding is free on most plans, but forwarded calls use airtime.
• AT&T and T-Mobile: **61*number# forwards when you don’t answer, and ##61# cancels it. **004*number# covers all the conditional cases at once — no answer, busy, or unreachable. The timer goes at the end, as in **61*number**15# for a wait of about 15 seconds. Put the full forwarding number where it says “number.”
• Internet-based business phone systems, bundled office systems and Google Voice: star codes don’t work on these. Look for call forwarding, ring groups or unanswered-call settings in the system’s app or web portal; Google documents its own steps in its Voice help pages.

Test it, then remember it’s on

Call your business line from another phone and let it ring out. Check three things: that the call lands where you expect, how many rings it took, and — if it’s going to an answering service — that they pick up with your business name, not theirs. Do it again from a different phone if you can.

Then keep track of it. Forwarding stays on until you turn it off, so when you no longer need it, use the cancel code or the portal switch and test once more. A forgotten forward is how a business ends up sending calls to a number nobody watches. Forwarding also has a quiet advantage: your number never moves, which matters if you’re weighing whether you can keep your number with an answering service. If you work alone and lose calls mostly while your hands are busy, this one setting is a sensible first step alongside the other everyday fixes.