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Gap percentage calculator

Enter yesterday's close and today's open. You get the gap in points, the gap as a percentage, and its direction.

How to use it

  1. Enter the prior close.
  2. Enter the open price.
  3. Read the gap in points, percent and direction.
Gap % = (open − prior close) ÷ prior close × 100
Example. Prior close 550.00, open 553.30: gap +3.30 points = +0.60% (gap up).

About this calculator

A gap is the difference between one session's close and the next session's open. Percentage gaps let you compare across instruments and price levels: a 3-point gap means something different on a 50-dollar stock than on SPY. This calculator describes the size of a gap only. It says nothing about whether the gap fills or continues.

Frequently asked questions

How do you calculate a gap percentage?
Subtract the prior close from the open, divide by the prior close and multiply by 100.
Does a gap always fill?
No. Some gaps fill quickly, some never do. This tool does not predict either outcome.
Can I use it for futures?
Yes. Enter the prior settlement or close and the new session's open.

Measuring the opening gap?

See SPY premarket levels: structure, key levels and catalysts in futures and SPY/QQQ terms, before the 9:30 ET open.

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Informational calculator for reference only. Outputs are arithmetic, not quotes, recommendations or trade signals. LiquidityLevels provides educational market commentary, not financial advice.