Rebar Weight & Length Calculator
Calculate rebar weight, number of bars, and lap splice requirements. Get accurate quantities for ordering reinforcement steel.
Total length of rebar needed for your project
Need a complete rebar takeoff from your blueprints? Our AI can extract all reinforcement quantities automatically.
Get Full Takeoff from PlansHow to Calculate Rebar Requirements
Accurate rebar calculations are essential for structural integrity and cost estimation. This guide explains how to determine weight, quantities, and lap splice requirements.
Rebar Weight Formula
Total Weight = Linear Feet x Weight per Foot
Each rebar size has a specific weight per linear foot. For example, #4 rebar weighs 0.668 lbs/ft, while #5 rebar weighs 1.043 lbs/ft.
Rebar Size Chart
| Bar Size | Diameter | Weight (lbs/ft) | Common Use |
|---|---|---|---|
| #3 | 3/8" | 0.376 | Stirrups, ties |
| #4 | 1/2" | 0.668 | Residential slabs, walls |
| #5 | 5/8" | 1.043 | Footings, beams |
| #6 | 3/4" | 1.502 | Foundations, columns |
| #7 | 7/8" | 2.044 | Heavy structural |
| #8 | 1" | 2.670 | Commercial foundations |
Lap Splice Requirements
When rebar must be spliced, the overlap length is critical for structural integrity:
- Minimum lap: 40x the bar diameter
- #4 rebar: 40 x 0.5" = 20" minimum lap
- #5 rebar: 40 x 0.625" = 25" minimum lap
- ACI code minimum: 12 inches regardless of bar size
Standard Bar Lengths
Pro Tip
Always add 5-10% extra for waste and cutting losses. Complex shapes and bends require additional material. For accurate counts on complex projects, use a professional takeoff from your structural drawings.
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