Guidance value is Karnataka's name, and guideline value Tamil Nadu's, for the minimum value the state sets per unit area for stamp duty. Market value is the price a willing buyer and seller agree. Duty is charged on whichever is higher; the guidance value is not an estimate of what a property is worth.
Side by side
Factor
Guidance value
Market value
Set by
State valuation committees
The market
Where the name is used
Karnataka (guidance), Tamil Nadu (guideline); other states use other names
Everywhere
Unit
Per square foot or metre, by street or area, and type
Per property
Stamp duty
The minimum base
The base when higher
Changes
When the state revises it
With demand and supply
Used by lenders
Sometimes as a reference
Their valuer's assessment
When Guidance value matters
Look up the guidance value before agreeing a price to estimate the minimum stamp duty and registration cost.
When Market value matters
Negotiate on market value, judged from comparable sales, not on the guidance value.
In more detail
Karnataka and Tamil Nadu publish their values online by area, street and property type. A property with features the table does not capture may sell well above or below it.
This page and the circle rate page describe the same idea under different state names; see that page for the income-tax point.