Our speed feed calculator covers milling, drilling, lathe turning, and tapping. Each operation uses different formulas — our calculator handles all of them automatically.
Our milling speed and feed calculator and feed and speed calculator milling handles end mills, face mills, slot mills, and ball end mills. Shows MRR and cycle time.
Our drill speed and feed calculator and drill speed feed calculator supports twist drills, carbide drills, and spade drills in any material from aluminum to Inconel.
Our feed and speed calculator lathe and lathe speed and feed calculator calculates turning speed from stock diameter. Works for OD turning, boring, and facing operations.
Our tapping calculator is synchronized: feed rate is auto-calculated from RPM and thread pitch/TPI. Works for UNC, UNF, metric M-series, and pipe threads.
Our free speed and feed calculator is more complete than Kennametal, FSWizard, and OmniCalculator — because it covers all 4 machining operations simultaneously, includes 30+ materials with tool-specific SFM values, calculates 6 key outputs (RPM, feed rate, chip load, MRR, cutting power, and cycle time), and supports both imperial and metric units. Whether you need a milling speed and feed calculator, drill speed and feed calculator, feed and speed calculator lathe, or a general feed and speed calculator, this single tool handles every CNC machining scenario.
Our feed and speed calculator uses this SFM database. SFM values assume sharp tooling, adequate coolant/lubrication, rigid machine setup, and moderate depth of cut. Reduce by 25–30% for interrupted cuts, poor fixturing, or dull tooling.
| Material | HSS SFM | Carbide SFM | Chip Load (0.5" mill) | Notes |
|---|---|---|---|---|
| Aluminum 6061 | 300 | 800 | 0.004" | Excellent machinability, 2-flute end mills preferred |
| Mild Steel 1018 | 100 | 350 | 0.002" | Good machinability, flood coolant recommended |
| Stainless 304 | 60 | 200 | 0.0015" | Work hardening — maintain chip load, don't dwell |
| Titanium Ti-6Al-4V | 25 | 100 | 0.001" | Low SFM, high pressure coolant required |
| Inconel 718 | 15 | 60 | 0.001" | Difficult — use coated carbide, flood coolant |
| Delrin Acetal | 400 | 1000 | 0.006" | Plastics machine fast — watch for melting |
The spindle speed (RPM) formula for all machining operations: RPM = (SFM × 3.82) ÷ Diameter (inches). The constant 3.82 = 12 ÷ π. In metric: RPM = (1000 × Vc) ÷ (π × D mm) where Vc is cutting speed in m/min. SFM comes from the material-tool combination. Higher SFM = faster cutting = more heat. Choose SFM conservatively when: setup is not rigid, tool is dull, cut is interrupted, or coolant is inadequate.
Our milling speed and feed calculator uses: Feed Rate (IPM) = RPM × Chip Load × Number of Flutes. Chip load (inches per tooth) is the thickness of the chip each cutting edge removes. Too high = tool breakage. Too low = rubbing, built-up edge, poor surface finish. Typical chip loads: aluminum 0.002–0.006", steel 0.001–0.003", titanium 0.0005–0.001".
Our drill speed feed calculator uses: Feed Rate (IPM) = RPM × Feed per Revolution (in/rev). Feed per revolution scales with drill diameter — larger drills use higher feed per revolution. Peck drilling: break chip every 1–2× drill diameter in depth.
Turning 2" diameter 304 stainless with carbide insert:
SFM (carbide + SS304) = 200 SFM
RPM = (200 × 3.82) ÷ 2.0" = 764 ÷ 2 = 382 RPM
Feed = 0.006 in/rev × 382 RPM = 2.3 IPM
DOC = 0.050" (light finish pass)
MRR = π × 2.0 × 0.050 × 2.3 = 0.72 in³/min
Cutting Power ≈ 0.72 × 0.5 (unit power for SS) = ~0.36 HP spindle
Pro tip — feed speed calculator starting points: When running a new material or tool combination for the first time, start at 75% of the calculated RPM and 60% of the calculated feed rate. Increase gradually while monitoring chip color (golden = good, blue = too hot), chip shape, surface finish, and spindle load. This conservative approach to our speed and feed calculator prevents expensive tool breakage on the first cut. Once you've validated the parameters, you can optimize toward the recommended values.
Questions about milling speed and feed, drill speed and feed, lathe speed calculations, chip load, and the formulas used in CNC machining.
The speed and feed calculator uses these core formulas: RPM = (SFM × 3.82) ÷ Tool Diameter (inches). Feed Rate (milling) = RPM × Chip Load × Number of Flutes. Feed Rate (drilling) = RPM × Feed per Revolution. Material Removal Rate = Feed Rate × Width of Cut × Depth of Cut. Cutting Power (HP) = MRR × Unit Power constant (0.3–1.5 HP/in³/min depending on material). Our feed speed calculator and feed and speed calculator calculates all of these simultaneously from your inputs.
For the milling speed and feed calculator and feed and speed calculator milling: 1) Select Milling operation tab. 2) Choose your material (e.g., 6061 aluminum). 3) Select tool material (solid carbide = highest speed, HSS = slower). 4) Enter end mill diameter (use presets for common sizes). 5) Set number of flutes (2 for aluminum, 4 for steel). 6) Enter depth of cut and width of cut. 7) Click Calculate. Results: RPM for your spindle, feed rate in IPM, chip load per tooth, MRR in in³/min, estimated HP, and cycle time. Start at 75% of these values when testing a new setup.
Our drill speed and feed calculator and drill speed feed calculator: 1) Select Drilling tab. 2) Choose workpiece material. 3) Select drill material (HSS for standard, carbide for production). 4) Enter drill diameter — use presets for letter, number, and fractional sizes. 5) Depth of cut = full hole depth. 6) Click Calculate. The drilling feed rate uses "feed per revolution" instead of chip load — typically 0.001–0.003 in/rev for small drills, 0.006–0.015 for drills over 1/2". Use peck drilling (retract every 1D depth) for holes deeper than 3× diameter. Reduce feed by 50% for blind holes near full depth.
Our lathe speed and feed calculator and feed and speed calculator lathe differs because on a lathe, the workpiece rotates (not the tool), and speed depends on stock diameter (OD) rather than tool diameter. RPM decreases as you take successive passes and the diameter gets smaller — constant SFM means increasing RPM as diameter shrinks. For CSS (constant surface speed) lathes, the machine adjusts RPM automatically. For manual/fixed RPM lathes: calculate RPM at starting OD, then recalculate for each 0.25–0.5" diameter reduction in roughing. Feed rate on lathe is typically 0.003–0.015 in/rev for finishing, 0.010–0.030 for roughing, much slower than milling IPM values.
Chip color in steel is a real-time indicator of heat at the cutting zone — our speed feed calculator gives target parameters but chip color tells you if you hit them. Silver/natural: too cold, may need higher speed or feed. Straw/golden (400–500°F): ideal — good chip load and speed. Blue (550–700°F): acceptable in steel, coolant recommended. Purple-blue (700–900°F): too hot — reduce speed or increase coolant. Black/burned: very high heat — reduce SFM immediately. In aluminum: chips should be shiny. Discoloration means melting — reduce speed or increase feed. In titanium: silver to straw is acceptable — blue means danger of combustion.