Price variation calculator for works contracts
Works out price variation by the index formula in your contract: each component's share of the work, its base index and its current index.
- Applies to
- Contracts with an index-linked price variation clause
- Rates
- Set per contract
- Last checked
- 10 November 2026
Inputs and result. Every rate is yours to set.
After the exclusions your contract lists, such as client-issued material and extra items at current rates.
Labour
Share, base, current
Cement
Share, base, current
Steel
Share, base, current
Other materials
Share, base, current
Fuel and lubricants
Share, base, current
Shares and indices are the example contract’s. Use the component shares in your contract and the published indices for the base month and the period.
Price variation payable
₹46,000
- Labour₹30,000.00
- Cement₹10,000.00
- Steelminus ₹15,000.00
- Other materials₹16,000.00
- Fuel and lubricants₹5,000.00
- Non-adjustable share20.0%
Rule applied. Price variation = value of work done in the period x the sum, for each component, of (share / 100) x (current index - base index) / base index. In CPWD contracts this is commonly known as clause 10CC. The components, shares, indices and exclusions come from your contract.
Last checked 10 November 2026
The steps behind the figure
- Take the value of work done in the period, after the exclusions your contract lists.
- For each component, find the base index for the base month and the current index for the period.
- Multiply the value by the component's share and by the change in its index over the base index.
- Add the components. A positive total is paid to you; a negative one is recovered.
- Value of work done, this bill20,84,879
- Retention, 5%- 1,04,244
- Mobilisation advance recovery- 1,50,000
- Interest on advance- 12,375
- Secured advance adjusted- 2,40,000
- Labour welfare cess, 1%- 20,849
- Income-tax TDS, 2%- 41,698
- GST TDS, 2%- 41,698
- GST on the invoice, 18%+ 3,75,278
- Recoveries, 7 lines- 6,10,864
- Net payable₹18,49,293
Which indices are used?
The ones your contract names, commonly published wholesale price and consumer price indices for each component. Use the month the contract sets for the base and for each period.
Can price variation be negative?
Yes. When an index falls below its base, that component is recovered from you.
Does Tatha Vastu fetch the indices?
You enter the base and current index for each period. Tatha Vastu applies your contract's formula and keeps each period's figures on the bill.