The Put-Call Ratio divides the put figure by the call figure across an option chain. Taken on open interest it compares standing positions; taken on volume it compares the session’s trading. It is one number divided by another, and nothing more.
Definition and Formula
PCR is computed by adding up the chosen figure across every put row in the chain, then across every call row. The first total is divided by the second. A result of 1.00 means the two totals are equal.
There are two PCRs and they answer different questions. The open-interest version compares positions that stand open, some of them opened days ago. The volume version compares what changed hands during this session alone. Presenting them as one number would blur two separate measurements.
The result depends on which strikes are included. A PCR taken across a window of a few strikes around the current price is one number. A PCR taken across the full chain is another, from the same data. Neither is wrong, but the two are not interchangeable.
When the call total is zero, the division has no answer. This site prints nothing in that case rather than a zero, because a printed zero reads as a real measurement.
The two totals that go into the ratio matter as much as the ratio itself. A PCR of 1.20 built on very small totals, and one built on very large totals, are the same number. They rest on quite different amounts of activity, and the ratio alone does not distinguish them. That is why this site prints the totals alongside.
PCR is also computed on different instruments in the same way. This makes the number comparable in form, but not always in substance. An index chain and a single stock chain differ in how many strikes are listed. They also differ in how far the strikes extend, and how much open interest sits far from the current price.
Formula: PCR (OI) = total put open interest ÷ total call open interest · PCR (Volume) = total put volume ÷ total call volume
A Worked Example
| Total call OI | 50,30,000.00 |
|---|---|
| Total put OI | 51,10,000.00 |
| Total call volume | 11,20,000.00 |
| Total put volume | 9,90,000.00 |
| PCR (Open Interest) | 1.02 |
|---|---|
| PCR (Volume) | 0.88 |
Both ratios are computed by the same code that builds the option chain pages on this site, from the four totals above.
What This Number Tells You
The ratio states the relation between two totals taken from the same chain at the same moment.
Read together with the totals it came from, it states whether the puts or the calls carry the larger figure. It also states by how much.
And What It Does Not Tell You
The ratio carries no direction. A high or a low reading is a relation between two counts. A count does not know which way a price will move.
It does not state why either total is what it is. Positions are opened for reasons the chain does not record, including hedging against holdings it cannot see.
A PCR from one site and a PCR from another may differ without either being wrong. This can happen because the strike window and the figure used may differ. Comparing two ratios means first checking that both were taken the same way.
Frequently Asked Questions
Which PCR does this site show?
Both, separately. The open-interest version and the volume version are printed as two rows, never combined into one number.
What does a PCR of 1.00 mean?
That the put total and the call total are equal for the strikes included. It is a statement about those two totals and nothing else.
Why can PCR be missing?
Because the call total was zero, which leaves the division without an answer. This site prints nothing in that place rather than a zero, since a zero would read as a measurement.
Does the strike window change the answer?
Yes. A ratio taken across a few strikes near the current price is one number. One taken across the whole chain is another, from the same data. This site states how many strikes its window covers.
Should the totals be read along with the ratio?
They are printed alongside for that reason. The same ratio can rest on very small or very large totals, and the ratio on its own does not say which.