Work Rate Calculator
Calculate how long two constant-rate workers, machines or pipes take together. Include an opposing drain and an already-completed fraction, with a progress graph.
YOUR CALCULATION
Result
—
Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Treat a complete job as 1. Divide 1 by each solo completion time to obtain rates in jobs per second. Add the rates, or subtract B when it removes progress. Divide the remaining fraction by the positive combined rate.
net rate = 1/tA ± 1/tB; remaining fraction = 1 − completed%/100; time = remaining fraction / net rate
Worked example
A needs 6 hours and B needs 12 hours alone. Working together their rate is 1/6 + 1/12 = 1/4 job per hour, so a complete job takes 4 hours. If B instead drains, the net rate is 1/12 job per hour and completion takes 12 hours.
Assumptions and input details
Both solo times refer to the same full-size job or tank and must be positive. Agents begin together and keep independent constant rates; coordination losses, variable flow, breaks and capacity constraints are not modelled. A zero or negative net rate cannot finish an incomplete job and is rejected. An already-completed job needs zero additional time. Time units are explicit; a day means 24 hours. This is a classroom rate model, not a promise of real work output.
References: OpenStax: work-rate applications
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
Add, subtract, multiply or divide fractions and mixed numbers. Follow exact fraction steps, simplification and a number-line diagram.
Add or subtract up to 100 durations. Use signed clock durations or decimal hours, minutes or seconds, then compare the exact total and running sums.
Solve two linear equations in x and y. See determinants, substitution checks and the two lines, including parallel or coincident cases.
Reserved advertising space.