Quick guide
How to use this calculator
- Enter both factors in each of the first two pairs.
- Add more pairs when needed.
- Read the exact total and open the list of individual products.
Calculation method
Multiply each pair, then add the products
For pairs (a₁,b₁) through (aₙ,bₙ), the calculator forms each exact product aᵢ×bᵢ.
It then aligns the product scales and adds them exactly. No intermediate product is rounded.
Worked example
Add two pair products
Multiply 0.1 by 0.2, multiply 1.5 by 2, then add those two exact products.
(0.1 × 0.2) + (1.5 × 2) = 0.02 + 3.0 = 3.02
Supported inputs
Precision and limits
Pair count
Enter between 2 and 100 ordered pairs.
Exact decimals
Each factor may contain up to 200 digits and 100 decimal places.
Bounded results
Each product is limited to 400 coefficient digits; aligning mixed scales across 100 pairs can produce a total of at most 602 coefficient digits.
No hidden rounding
Every accepted pair product and the final sum use exact integer-backed decimal arithmetic.