Is a chess clock app as accurate as a real chess clock?

Yes. Modern phones keep time to the millisecond, which is more precise than the mechanical clocks used for over a century and on par with digital hardware. Apps like Chess Clock also show tenths of a second when time runs low, which many hardware clocks do not.

Can I use a phone as a chess clock in a rated tournament?

Usually not. FIDE-rated events ban phones from the playing area, and USCF rules call for approved standard equipment, so a phone app can be refused. For rated over-the-board play you still need a dedicated clock; for everything else an app does the job.

Does a chess clock app work without internet?

Completely. Chess Clock runs entirely on the device with no account and no connection required — airplane mode is actually recommended so notifications never interrupt a game.

Won't the phone screen turn off during a long game?

No. A proper clock app keeps the screen awake for the entire game, so the clock never disappears behind a lock screen even during a long think.

What time controls does a clock app support that hardware doesn't?

Beyond the usual Fischer, Bronstein, and delay modes, Chess Clock offers byo-yomi periods, hourglass mode, multi-phase tournament controls, and time-odds setups where each player gets a different time control — combinations most hardware clocks can't match, and all far easier to configure.

Why use a chess clock app on your phone?

A chess clock app turns the phone you already carry into a full tournament-grade timer: every time control a $40–100 hardware clock offers (Fischer, Bronstein, US delay, multi-phase, byo-yomi) with to-the-tenth precision, at no cost. For casual games, club nights, and travel it is the most practical clock you can own — only some rated over-the-board events still require approved dedicated hardware.

The best chess clock is the one you have with you

Chess happens where people meet: a park bench, a café table, a school lunchroom, a hotel lobby on a work trip, a friend's kitchen after dinner. Nobody carries a DGT clock to any of those places — but everyone carries a phone. With a clock app installed, a pocket chess set or the café's house board becomes a real timed game in seconds.

That spontaneity matters more than it sounds. The difference between "we should play sometime" and actually playing five games of blitz is usually just having a clock within reach. A phone removes the last piece of friction from over-the-board chess.

Free versus $40–100 of dedicated hardware

A decent digital chess clock costs real money: entry-level digital clocks start around $40, and the DGT 3000-class clocks used at top events run closer to $100. That is a reasonable purchase for a tournament regular — and an unnecessary one for everyone else.

An app costs nothing to try and covers everything the hardware does. Chess Clock includes bullet, blitz, rapid, classical, and hourglass presets for free, and even its full Pro tier — tournament controls, Bronstein, byo-yomi, multi-phase FIDE and USCF settings — is a small one-time purchase, not a subscription. You would struggle to find a hardware clock at any price that does more.

More time controls than any hardware clock

Physical clocks are limited by their firmware and their two-line displays. Setting a multi-phase control on a hardware clock often means a manual and five minutes of button presses. On a phone, the same setup is a couple of taps, and the options go further:

Every increment style: Fischer (applied before or after the move), Bronstein delay, simple US delay, or none.
Real tournament controls: the FIDE classical standard (90 minutes for 40 moves plus 30 minutes, with a 30-second increment from move one), USCF delay controls, and multi-phase controls with move counts.
Formats hardware rarely handles well: byo-yomi periods for Go and shogi players, hourglass mode, and tiebreak presets.
Time odds: each player can have a completely different time control — 5 minutes versus 2, or increment for one side only — which is the classic way to make a game between uneven players competitive.

Add to that things hardware simply cannot do: 16 themes from a warm wood look to true-black OLED dark mode, halves that rotate independently so each player reads their time right-side up, and a game history that records moves, time used, and average time per move so you can see where your clock actually went.

Quiet, precise, and polite: using a phone clock well

A few habits make a phone clock work as smoothly as dedicated hardware:

Airplane mode is etiquette. A notification mid-scramble is worse than any hardware quirk. Switch to airplane mode before the first game — Chess Clock can remind you — and the clock runs perfectly offline, with no ads, tracking, or account to interfere.
Silence the sounds where it matters. In a library, a classroom, or a quiet club room, turn tap sounds off and rely on the visual turn indicator.
The screen stays awake. A good clock app disables auto-lock while a game runs, so the display never dims out from under a long think.
Place it like a clock. Set the phone beside the board where a clock would sit — on White's right or wherever the players agree — and press with the same hand that moved, exactly as with hardware.

When you still need a dedicated hardware clock

Honesty matters here: phones are not welcome everywhere. FIDE-rated events generally ban phones from the playing hall entirely, and many USCF tournaments require an approved delay-capable clock — a phone app does not qualify as standard equipment, and an arbiter can refuse it even if both players are willing. If you play rated over-the-board tournaments, buy a proper clock; that is what it is for.

For everything else — casual games, skittles between rounds, club nights, teaching kids, coffeehouse blitz, travel — the app in your pocket is not a compromise. It is more capable, more precise, and infinitely more likely to actually be there when someone says "want a game?"

Turn your iPhone into a real chess clock

Chess Clock gives you every time control from Bullet to FIDE Classical — beautiful, precise, and completely private.

Coming soon to the App Store