Free calculators for contractors
18 calculators for tendering, billing, site estimation and deadlines — built around the rules Indian government contractors work with: CPWD, MoRTH and state PWD tenders, GST, TDS, the MSMED Act and more. Free to use, no sign-up needed.
Tender & bidding
Check eligibility and work out bid securities before you quote.
Bid capacity
(M × A × N) − B, with work already in hand pulled from your active contracts.
Tender eligibility checker
Similar-works (3 × 40%, 2 × 50%, 1 × 80%) and turnover tests using your past work.
Below-estimate bid security
How far below estimate you are, and the extra performance security a low bid triggers.
EMD calculator
Earnest money deposit as a percentage of the estimated tender value.
Performance guarantee
Performance bank guarantee as a percentage of the contract value.
Bills & payments
Know what actually reaches your bank, and claim what you're owed.
Running bill deductions
Gross bill → net amount in your bank after TDS, GST TDS, cess, retention and recoveries.
MSME late-payment interest
Interest owed on delayed payments under the MSMED Act — 3× RBI bank rate, compounded monthly.
Price escalation (10CC)
Claim cost increases using the price-variation formula and WPI / CPI indices.
Delay penalty & extension of time
Liquidated damages for late completion, capped, after hindrances you can claim time for.
Mobilisation advance planner
Advance amount, interest and a month-by-month recovery schedule against your bills.
GST quote calculator
Add GST to a base amount, or back the base out of a GST-inclusive total.
Site & estimation
Quantities, units, labour and rates for pricing work.
Material quantities
Cement, sand, aggregate, bricks, steel, plaster and paint for a given job.
Site unit converter
Brass, cft, m³, bigha, katha, gaj and more — plus steel bars per tonne.
Rate analysis
Build an item rate from materials, labour, sundries and overheads; compare with SOR.
Labour cost & compliance
True monthly cost of your crew with EPF, ESI and bonus — and what workers take home.
Dates & reminders
Never miss a bid deadline, guarantee expiry or deposit release.
Tender deadline planner
Work back from the bid due date: documents, EMD, DSC check, uploads. Add to calendar.
Bid & guarantee validity
Bid validity, EMD and performance guarantee expiry dates — plus deposits due back to you.
Retention release tracker
When each contract's security deposit and retention becomes due for release.
Let the calculators fill themselves in
With a free Digi Karya account, these tools pull in your own contracts, tenders, bills and documents — and you also get licence and GST expiry reminders, a tender workspace, milestone billing and EMD & bank guarantee tracking.