Coin Flip

What is an online coin flip?

An online coin flip is a virtual coin toss that gives you heads or tails with a 50/50 chance, without needing a real coin. This coin flip tool shows a 3D coin that spins and lands on the result, keeps a running count of heads and tails, tracks the longest streaks and lists every result in order. You can flip once to settle a decision, or flip 10 or 100 times in one click to explore probability, run a classroom experiment or simulate a series of tosses.

The result is decided by your browser's cryptographic random number generator, not by the animation, so every flip is independent and fair.

How to use this tool

1. Tap the coin or press "Flip once" for a single heads-or-tails result.
2. Press "Flip 10 times" or "Flip 100 times" to toss in bulk. The coin shows the last result and the totals include the whole batch.
3. Read the totals — heads and tails counts with percentages, current streak and the longest run of each side.
4. Scan the history — every flip appears as an H or T chip, oldest first.
5. Copy the results as text, or press Reset to start a new session.

How the coin toss works

Each flip reads one random byte from crypto.getRandomValues() and looks at its lowest bit: 1 means heads, 0 means tails. Exactly half of all 256 byte values have each bit value, so the probability is exactly 50% for each side. Flips never depend on earlier flips — the coin has no memory.

Worked example: the chance of heads on one flip is 1/2. The chance of 3 heads in a row is 1/2 × 1/2 × 1/2 = 1/8 = 12.5%. The chance of 10 heads in a row is (1/2)¹⁰ = 1/1,024, about 0.098%. In 100 flips you should expect about 50 heads, but a result anywhere from roughly 40 to 60 is completely normal (that range covers about 96% of 100-flip sessions). Long streaks are also normal: in 100 fair flips, the longest run of the same side is usually around 6 or 7.

Probability of multiple coin flips

When you flip several coins, the number of heads follows a binomial distribution. The chance of exactly k heads in n flips is C(n, k) ÷ 2ⁿ, where C(n, k) is the number of ways to choose which flips are heads. For example, exactly 5 heads in 10 flips has C(10, 5) = 252 possible arrangements out of 2¹⁰ = 1,024, so the probability is 252 ÷ 1,024 = 24.6%. That surprises many people: the "perfect" 50/50 split happens in fewer than one in four sessions of 10 flips. The chance of getting at least one heads in 3 flips is 1 − (1/2)³ = 7/8 = 87.5%. Use the "Flip 10 times" button repeatedly and watch how often the batch line shows exactly 5 heads.

Uses for a virtual coin toss

• Quick decisions: who goes first, which of two restaurants, which movie.
• Sports and games: deciding the toss in a friendly cricket or football match, or who serves first.
• Maths lessons: show the law of large numbers — percentages swing a lot after 10 flips and settle closer to 50% after hundreds.
• Probability practice: count streaks and compare them with the expected values above.
• Breaking ties when two options are equally good.

Tips

• Agree on who calls heads before you flip, especially when the toss settles something between people.
• For a best-of-three, flip three times and look at the last batch line — or flip once at a time and count.
• Do not expect "balancing": after five heads, tails is still exactly a 50% chance. Believing otherwise is called the gambler's fallacy.
• If you need more than two options, use the Spin the Wheel or Dice Roller tools instead.

Limitations & notes

A virtual coin is a model of an ideal fair coin. Real coins can be very slightly biased by their weight, how they are tossed and how they are caught, so results from this tool will not exactly match physical experiments. History is kept only in this page and clears when you refresh; the history display shows the most recent 500 flips, while totals and the copied text include every flip in the session. Nothing is sent to a server.

Frequently Asked Questions

Is this coin flip fair?

Yes. Each flip uses one bit from your browser's cryptographic random number generator, which gives exactly a 50% chance of heads and 50% chance of tails, independent of every earlier flip.

Does the animation affect the result?

No. The result is chosen first and the 3D coin is then rotated to show that side. The animation is only for display.

Why did I get more heads than tails in 10 flips?

Small samples vary a lot. Getting 6, 7 or even 8 heads out of 10 happens regularly with a fair coin. Flip 100 or more times and the percentage usually moves closer to 50%.

What is the chance of getting heads 5 times in a row?

One half multiplied by itself five times: (1/2) to the power 5 = 1/32, or about 3.1%. It is unlikely on any particular five flips but will happen often if you flip hundreds of times.

Can I flip more than 100 coins?

Yes. Press "Flip 100 times" as often as you like; totals and streaks keep adding up for the whole session until you press Reset.

Can I use this for a cricket toss?

Yes, for friendly matches. Let the visiting captain call heads or tails before you tap the coin. Official matches follow their own rules and use a physical coin.

Related tools

Dice Roller · Spin the Wheel · Decision Maker · Probability Calculator · Random Number Generator